feat(meshcore): opt-in auto-retry for automated channel sends on zero-heard miss (#3979) (#3988)

Part 2 of #3979 (builds on merged Part 1, PR #3987, which made the
"heard repeaters" echo-attribution trustworthy).

A MeshCore channel/broadcast send is an unacked, fire-and-forget flood, so
there is no firmware ACK to confirm delivery. When the Part 1 echo signal
reports that ZERO repeaters re-flooded our packet within 30s, the message
likely reached no one. This adds an opt-in, one-shot resend for that case.

- New global setting `meshcoreChannelRetryEnabled` (default OFF), wired through
  VALID_SETTINGS_KEYS, SettingsContext, and a new "MeshCore Messaging" section
  in global Settings (SettingsTab).
- Applies to AUTOMATED channel senders only (Automation Engine
  action.sendMessage, Auto-Acknowledge, auto-responder, auto-announce, timer
  triggers), threaded via a new `autoRetryOnMiss` opt-in flag on
  sendMessage/sendMessageWithResult/performScopedSend. User-initiated route
  sends never opt in, so they never retry.
- New channel-retry state machine (`pendingChannelRetries`,
  `maybeArmChannelRetry`, `handleChannelRetryTimeout`) parallel to and
  non-colliding with the DM ack-retry (#3977/#3980): the DM path keys on the
  firmware ACK CRC (toPublicKey set); the channel path keys on the echo-heard
  signal (channelIdx set) — mutually exclusive branches of performScopedSend.
- One-shot: the resend goes out with isAutoRetry=true (no new message row, no
  `message`/bus emit — so it cannot spawn a fresh automation) and
  autoRetryOnMiss=false (re-registered for echo correlation but never re-armed).
- Pending channel retries cleared in the disconnect() bulk cleanup.
- Tests: src/server/meshcoreManager.channelRetry.test.ts covers zero-heard
  resend, heard→no-resend, no-bus-reentry, one-shot, user-send never arms,
  setting-off never arms, disconnect clears, and DM/channel non-collision.
- Docs: docs/features/meshcore.md (new section) + automation-engine.md note.

Closes #3979


Claude-Session: https://claude.ai/code/session_015AFBA76hsjqhsXe1BdnYub

Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

Author: Yeraze

docs/features/automation-engine.md

@@ -189,6 +189,14 @@ Sends text to a channel or as a DM, with full `{{ }}` token interpolation in the
 The overall send is a **source × channel matrix**: each selected source posts to the matching local
 slot of each selected channel.
 
+> **MeshCore channel-send auto-retry** — because a MeshCore channel/broadcast send is an unacked
+> flood, the `Send message` action (like every automated MeshCore channel sender) can optionally be
+> resent once if no repeater is heard re-flooding it within 30 seconds. This is a global, opt-in,
+> one-shot behavior (off by default) configured in **Settings → MeshCore Messaging**; it never
+> retries user-typed messages, never retries direct messages (those have their own always-on ACK
+> retry), and the resend can never trigger a fresh automation. See
+> [Automated Channel-Send Auto-Retry](/features/meshcore#automated-channel-send-auto-retry).
+
 ### Manage the node
 
 Runs an admin/management operation on the subject node: **Favorite / Unfavorite**, **Ignore /

docs/features/meshcore.md

@@ -429,6 +429,20 @@ Timer Triggers schedule recurring actions independent of incoming traffic:
 - **Three actions** — send a **text** message (token expansion supported) to a channel or contact, fire a MeshCore **advert**, or **run a script** (token-expanded args).
 - **Last-run telemetry** — the UI surfaces the last fire time and outcome per trigger.
 
+## Automated Channel-Send Auto-Retry
+
+MeshCore channel (broadcast) messages are unacked, fire-and-forget floods — unlike a direct message, there is no firmware ACK to confirm delivery. MeshMonitor instead listens for nearby repeaters re-flooding your own packet (the "heard repeaters" signal, see [Message route line](#message-route-line)). When **no** repeater is heard, the message likely reached no one.
+
+The **MeshCore Messaging** section of global **Settings** hosts an opt-in toggle, **Auto-retry automated MeshCore channel sends** (default **off**). When enabled:
+
+- An **automated** channel send that hears **zero** repeaters within **30 seconds** is resent **exactly once**.
+- It applies only to automated senders: the [Automation Engine](/features/automation-engine) `Send message` action, Auto-Acknowledge, the [Auto-Responder](#auto-responder), [Auto-Announce](#auto-announce), and [Timer Triggers](#timer-triggers).
+- **User-initiated sends are never retried** — a message you type into the send bar goes out once regardless of this setting.
+- It is **one-shot**: the resend is never itself retried, so at most one extra transmission ever occurs per logical send.
+- The resend does **not** create a second message bubble and does **not** re-enter the automation event bus, so it can never trigger a fresh automation.
+
+This is **distinct from the direct-message retry**, which is always on and follows the firmware's own same-path/flood ACK cadence. Because a channel send has no delivery ACK, the retry can only guess from the heard-repeater signal — so with this enabled you may occasionally see a duplicate on the mesh if a late echo arrives right around the 30-second mark. Leave it off if duplicates are unacceptable for your deployment.
+
 ## Room Servers
 
 Room servers (advType=3) are BBS-style MeshCore nodes that store posts and push-sync them to connected clients. The **Rooms** view in the MeshCore page lists discovered room servers and provides:

src/components/SettingsTab.tsx

@@ -94,7 +94,7 @@ interface SettingsTabProps {
 }
 
 const GLOBAL_SECTIONS = new Set([
-  'settings-language', 'settings-units', 'settings-appearance', 'settings-link-previews', 'settings-map',
+  'settings-language', 'settings-units', 'settings-appearance', 'settings-link-previews', 'settings-meshcore-messaging', 'settings-map',
   'settings-security',
   'settings-apprise-server', 'settings-backup', 'settings-channel-database',
   'settings-maintenance', 'settings-auto-upgrade', 'settings-analytics',
@@ -179,6 +179,8 @@ const SettingsTab: React.FC<SettingsTabProps> = ({
     setEnableAudioNotifications,
     linkPreviewsEnabled,
     setLinkPreviewsEnabled,
+    meshcoreChannelRetryEnabled,
+    setMeshcoreChannelRetryEnabled,
     nodeDimmingEnabled,
     setNodeDimmingEnabled,
     nodeDimmingStartHours,
@@ -240,6 +242,7 @@ const SettingsTab: React.FC<SettingsTabProps> = ({
   const [localPacketLogMaxCount, setLocalPacketLogMaxCount] = useState(1000);
   const [localPacketLogMaxAgeHours, setLocalPacketLogMaxAgeHours] = useState(24);
   const [localLinkPreviewsEnabled, setLocalLinkPreviewsEnabled] = useState(linkPreviewsEnabled);
+  const [localMeshcoreChannelRetryEnabled, setLocalMeshcoreChannelRetryEnabled] = useState(meshcoreChannelRetryEnabled);
   const [localSolarMonitoringEnabled, setLocalSolarMonitoringEnabled] = useState(solarMonitoringEnabled);
   const [localSolarMonitoringLatitude, setLocalSolarMonitoringLatitude] = useState(solarMonitoringLatitude);
   const [localSolarMonitoringLongitude, setLocalSolarMonitoringLongitude] = useState(solarMonitoringLongitude);
@@ -337,6 +340,10 @@ const SettingsTab: React.FC<SettingsTabProps> = ({
           const linkPreviewsOn = !(settings.linkPreviewsEnabled === '0' || settings.linkPreviewsEnabled === 'false');
           setLocalLinkPreviewsEnabled(linkPreviewsOn);
 
+          // Load MeshCore channel-send auto-retry (#3979). Absent key => disabled.
+          const meshcoreChannelRetryOn = settings.meshcoreChannelRetryEnabled === '1' || settings.meshcoreChannelRetryEnabled === 'true';
+          setLocalMeshcoreChannelRetryEnabled(meshcoreChannelRetryOn);
+
           // Load LocalStats interval setting
           const statsInterval = parseInt(settings.localStatsIntervalMinutes || '15', 10);
           setLocalLocalStatsIntervalMinutes(statsInterval);
@@ -407,13 +414,14 @@ const SettingsTab: React.FC<SettingsTabProps> = ({
     setLocalNodeHopsCalculation(nodeHopsCalculation);
     setLocalDashboardSortOption(preferredDashboardSortOption);
     setLocalLinkPreviewsEnabled(linkPreviewsEnabled);
+    setLocalMeshcoreChannelRetryEnabled(meshcoreChannelRetryEnabled);
     setLocalSolarMonitoringEnabled(solarMonitoringEnabled);
     setLocalSolarMonitoringLatitude(solarMonitoringLatitude);
     setLocalSolarMonitoringLongitude(solarMonitoringLongitude);
     setLocalSolarMonitoringAzimuth(solarMonitoringAzimuth);
     setLocalSolarMonitoringDeclination(solarMonitoringDeclination);
     setLocalHideIncompleteNodes(!showIncompleteNodes);
-  }, [maxNodeAgeHours, inactiveNodeThresholdHours, inactiveNodeCheckIntervalMinutes, inactiveNodeCooldownHours, temperatureUnit, distanceUnit, positionHistoryLineStyle, telemetryVisualizationHours, favoriteTelemetryStorageDays, preferredSortField, preferredSortDirection, timeFormat, dateFormat, mapTileset, mapPinStyle, nodeHopsCalculation, preferredDashboardSortOption, linkPreviewsEnabled, solarMonitoringEnabled, solarMonitoringLatitude, solarMonitoringLongitude, solarMonitoringAzimuth, solarMonitoringDeclination, showIncompleteNodes, defaultMapCenterLat, defaultMapCenterLon, defaultMapCenterZoom, defaultLandingPage, appearanceMode, darkTheme, lightTheme]);
+  }, [maxNodeAgeHours, inactiveNodeThresholdHours, inactiveNodeCheckIntervalMinutes, inactiveNodeCooldownHours, temperatureUnit, distanceUnit, positionHistoryLineStyle, telemetryVisualizationHours, favoriteTelemetryStorageDays, preferredSortField, preferredSortDirection, timeFormat, dateFormat, mapTileset, mapPinStyle, nodeHopsCalculation, preferredDashboardSortOption, linkPreviewsEnabled, meshcoreChannelRetryEnabled, solarMonitoringEnabled, solarMonitoringLatitude, solarMonitoringLongitude, solarMonitoringAzimuth, solarMonitoringDeclination, showIncompleteNodes, defaultMapCenterLat, defaultMapCenterLon, defaultMapCenterZoom, defaultLandingPage, appearanceMode, darkTheme, lightTheme]);
 
   // Default solar monitoring lat/long to device position if still at 0
   useEffect(() => {
@@ -475,6 +483,7 @@ const SettingsTab: React.FC<SettingsTabProps> = ({
       localSolarMonitoringAzimuth !== solarMonitoringAzimuth ||
       localSolarMonitoringDeclination !== solarMonitoringDeclination ||
       localLinkPreviewsEnabled !== linkPreviewsEnabled ||
+      localMeshcoreChannelRetryEnabled !== meshcoreChannelRetryEnabled ||
       localHideIncompleteNodes !== !showIncompleteNodes ||
       localHomoglyphEnabled !== initialHomoglyphEnabled ||
       localLocalStatsIntervalMinutes !== initialLocalStatsIntervalMinutes ||
@@ -491,6 +500,7 @@ const SettingsTab: React.FC<SettingsTabProps> = ({
       localSolarMonitoringEnabled, localSolarMonitoringLatitude, localSolarMonitoringLongitude, localSolarMonitoringAzimuth, localSolarMonitoringDeclination,
       solarMonitoringEnabled, solarMonitoringLatitude, solarMonitoringLongitude, solarMonitoringAzimuth, solarMonitoringDeclination,
       localLinkPreviewsEnabled, linkPreviewsEnabled,
+      localMeshcoreChannelRetryEnabled, meshcoreChannelRetryEnabled,
       localHideIncompleteNodes, showIncompleteNodes, localHomoglyphEnabled, initialHomoglyphEnabled,
       localLocalStatsIntervalMinutes, initialLocalStatsIntervalMinutes,
       nodeDimmingEnabled, nodeDimmingStartHours, nodeDimmingMinOpacity, initialNodeDimmingSettings,
@@ -533,6 +543,7 @@ const SettingsTab: React.FC<SettingsTabProps> = ({
     setLocalSolarMonitoringAzimuth(solarMonitoringAzimuth);
     setLocalSolarMonitoringDeclination(solarMonitoringDeclination);
     setLocalLinkPreviewsEnabled(linkPreviewsEnabled);
+    setLocalMeshcoreChannelRetryEnabled(meshcoreChannelRetryEnabled);
     setLocalHideIncompleteNodes(!showIncompleteNodes);
     setLocalHomoglyphEnabled(initialHomoglyphEnabled);
     setLocalLocalStatsIntervalMinutes(initialLocalStatsIntervalMinutes);
@@ -548,7 +559,7 @@ const SettingsTab: React.FC<SettingsTabProps> = ({
       dateFormat, mapTileset, mapPinStyle, iconStyle, neighborInfoMinZoom, defaultMapCenterLat, defaultMapCenterLon, defaultMapCenterZoom, defaultLandingPage, appearanceMode, darkTheme, lightTheme, nodeHopsCalculation, preferredDashboardSortOption,
       initialPacketMonitorSettings, solarMonitoringEnabled, solarMonitoringLatitude,
       solarMonitoringLongitude, solarMonitoringAzimuth, solarMonitoringDeclination, showIncompleteNodes,
-      linkPreviewsEnabled,
+      linkPreviewsEnabled, meshcoreChannelRetryEnabled,
       initialHomoglyphEnabled, initialLocalStatsIntervalMinutes, initialNodeDimmingSettings,
       setNodeDimmingEnabled, setNodeDimmingStartHours, setNodeDimmingMinOpacity,
       initialAnalyticsProvider, initialAnalyticsConfig, initialAppriseApiServerUrl]);
@@ -601,6 +612,7 @@ const SettingsTab: React.FC<SettingsTabProps> = ({
         solarMonitoringAzimuth: localSolarMonitoringAzimuth.toString(),
         solarMonitoringDeclination: localSolarMonitoringDeclination.toString(),
         linkPreviewsEnabled: localLinkPreviewsEnabled ? '1' : '0',
+        meshcoreChannelRetryEnabled: localMeshcoreChannelRetryEnabled ? '1' : '0',
         hideIncompleteNodes: localHideIncompleteNodes ? '1' : '0',
         homoglyphEnabled: String(localHomoglyphEnabled),
         localStatsIntervalMinutes: localLocalStatsIntervalMinutes.toString(),
@@ -653,6 +665,7 @@ const SettingsTab: React.FC<SettingsTabProps> = ({
       onSolarMonitoringAzimuthChange(localSolarMonitoringAzimuth);
       onSolarMonitoringDeclinationChange(localSolarMonitoringDeclination);
       setLinkPreviewsEnabled(localLinkPreviewsEnabled);
+      setMeshcoreChannelRetryEnabled(localMeshcoreChannelRetryEnabled);
       setShowIncompleteNodes(!localHideIncompleteNodes);
 
       // Update initial packet monitor settings after successful save
@@ -683,7 +696,7 @@ const SettingsTab: React.FC<SettingsTabProps> = ({
       localTimeFormat, localDateFormat, localMapTileset, localMapPinStyle, localIconStyle, localNeighborInfoMinZoom, localDefaultMapCenterLat, localDefaultMapCenterLon, localDefaultMapCenterZoom, localDefaultLandingPage, localAppearanceMode, localDarkTheme, localLightTheme, getLocalEffectiveTheme,
       localNodeHopsCalculation, localDashboardSortOption, localPacketLogEnabled, localPacketLogMaxCount, localPacketLogMaxAgeHours,
       localSolarMonitoringEnabled, localSolarMonitoringLatitude, localSolarMonitoringLongitude,
-      localSolarMonitoringAzimuth, localSolarMonitoringDeclination, localLinkPreviewsEnabled, setLinkPreviewsEnabled, localHideIncompleteNodes, localHomoglyphEnabled, localLocalStatsIntervalMinutes,
+      localSolarMonitoringAzimuth, localSolarMonitoringDeclination, localLinkPreviewsEnabled, setLinkPreviewsEnabled, localMeshcoreChannelRetryEnabled, setMeshcoreChannelRetryEnabled, localHideIncompleteNodes, localHomoglyphEnabled, localLocalStatsIntervalMinutes,
       onMaxNodeAgeChange, onInactiveNodeThresholdHoursChange, onInactiveNodeCheckIntervalMinutesChange,
       onInactiveNodeCooldownHoursChange, onTemperatureUnitChange, onDistanceUnitChange, onPositionHistoryLineStyleChange,
       onTelemetryVisualizationChange, onFavoriteTelemetryStorageDaysChange, onPreferredSortFieldChange,
@@ -824,6 +837,7 @@ const SettingsTab: React.FC<SettingsTabProps> = ({
       setLocalSolarMonitoringAzimuth(0);
       setLocalSolarMonitoringDeclination(30);
       setLocalLinkPreviewsEnabled(true);
+      setLocalMeshcoreChannelRetryEnabled(false);
 
       // Update parent component with defaults
       onMaxNodeAgeChange(24);
@@ -849,6 +863,7 @@ const SettingsTab: React.FC<SettingsTabProps> = ({
       onSolarMonitoringAzimuthChange(0);
       onSolarMonitoringDeclinationChange(30);
       setLinkPreviewsEnabled(true);
+      setMeshcoreChannelRetryEnabled(false);
 
       // Update initial packet monitor settings
       setInitialPacketMonitorSettings({ enabled: false, maxCount: 1000, maxAgeHours: 24 });
@@ -1076,6 +1091,7 @@ const SettingsTab: React.FC<SettingsTabProps> = ({
         { id: 'settings-sorting', label: t('settings.sorting') },
         { id: 'settings-appearance', label: t('settings.appearance') },
         { id: 'settings-link-previews', label: t('settings.link_previews', 'Link Previews') },
+        { id: 'settings-meshcore-messaging', label: t('settings.meshcore_messaging', 'MeshCore Messaging') },
         { id: 'settings-map', label: t('settings.map') },
         { id: 'settings-node-display', label: t('settings.node_display') },
         { id: 'settings-telemetry', label: t('settings.telemetry') },
@@ -1378,6 +1394,23 @@ const SettingsTab: React.FC<SettingsTabProps> = ({
           </p>
         </div>}
 
+        {show('settings-meshcore-messaging') && <div id="settings-meshcore-messaging" className="settings-section">
+          <h3 style={{ display: 'flex', alignItems: 'center', gap: '0.75rem' }}>
+            <label style={{ display: 'flex', alignItems: 'center', gap: '0.5rem', margin: 0, cursor: 'pointer' }}>
+              <input
+                type="checkbox"
+                checked={localMeshcoreChannelRetryEnabled}
+                onChange={(e) => setLocalMeshcoreChannelRetryEnabled(e.target.checked)}
+                style={{ cursor: 'pointer' }}
+              />
+              <span>{t('settings.meshcore_channel_retry_enabled', 'Auto-retry automated MeshCore channel sends')}</span>
+            </label>
+          </h3>
+          <p className="setting-description">
+            {t('settings.meshcore_channel_retry_description', 'When enabled, an AUTOMATED MeshCore channel/broadcast message (Automation Engine, Auto-Acknowledge, auto-responder, auto-announce and timer triggers) that hears no repeaters within 30 seconds is resent exactly once. User-initiated sends are never retried. This is opt-in, channel-only, and one-shot — distinct from the always-on retry for direct messages. You may occasionally see a duplicate on the mesh.')}
+          </p>
+        </div>}
+
         {show('settings-map') && <div id="settings-map" className="settings-section">
           <h3>{t('settings.map')}</h3>
           <div className="setting-item">

src/contexts/SettingsContext.tsx

@@ -106,6 +106,12 @@ interface SettingsContextType {
   enableAudioNotifications: boolean;
   /** Global toggle: fetch & render OpenGraph link preview cards for URLs in messages. */
   linkPreviewsEnabled: boolean;
+  /**
+   * Global opt-in (issue #3979, default false): auto-retry an AUTOMATED MeshCore
+   * channel send once, 30s later, when zero repeaters were heard. Automated
+   * senders only; never user-initiated sends. Distinct from the DM ack-retry.
+   */
+  meshcoreChannelRetryEnabled: boolean;
   nodeDimmingEnabled: boolean;
   nodeDimmingStartHours: number;
   nodeDimmingMinOpacity: number;
@@ -154,6 +160,7 @@ interface SettingsContextType {
   setSolarMonitoringDeclination: (declination: number) => void;
   setEnableAudioNotifications: (enabled: boolean) => void;
   setLinkPreviewsEnabled: (enabled: boolean) => void;
+  setMeshcoreChannelRetryEnabled: (enabled: boolean) => void;
   mutedChannels: MutedChannel[];
   mutedDMs: MutedDM[];
   muteChannel: (channelId: number, muteUntil: number | null) => Promise<void>;
@@ -418,6 +425,11 @@ export const SettingsProvider: React.FC<SettingsProviderProps> = ({ children, ba
   // the previous always-on behavior; loaded from the server in loadServerSettings.
   const [linkPreviewsEnabled, setLinkPreviewsEnabledState] = useState<boolean>(true);
 
+  // MeshCore automated-channel-send auto-retry (issue #3979) - server-backed
+  // (global). Defaults to false (opt-in); loaded from the server in
+  // loadServerSettings.
+  const [meshcoreChannelRetryEnabled, setMeshcoreChannelRetryEnabledState] = useState<boolean>(false);
+
   // Node dimming settings - localStorage only
   const [nodeDimmingEnabled, setNodeDimmingEnabledState] = useState<boolean>(() => {
     const saved = localStorage.getItem('nodeDimmingEnabled');
@@ -822,6 +834,11 @@ export const SettingsProvider: React.FC<SettingsProviderProps> = ({ children, ba
     setLinkPreviewsEnabledState(enabled);
   };
 
+  // MeshCore channel-retry setter updates state only - persisted server-side
+  const setMeshcoreChannelRetryEnabled = (enabled: boolean) => {
+    setMeshcoreChannelRetryEnabledState(enabled);
+  };
+
   // Solar monitoring setters update state only - values are persisted server-side
   const setSolarMonitoringEnabled = (enabled: boolean) => {
     setSolarMonitoringEnabledState(enabled);
@@ -1328,6 +1345,13 @@ export const SettingsProvider: React.FC<SettingsProviderProps> = ({ children, ba
             setLinkPreviewsEnabledState(enabled);
           }
 
+          // MeshCore channel-send auto-retry (#3979) - database-only. Absent key
+          // means default (disabled); only an explicit '1'/'true' turns it on.
+          if (settings.meshcoreChannelRetryEnabled !== undefined) {
+            const enabled = settings.meshcoreChannelRetryEnabled === '1' || settings.meshcoreChannelRetryEnabled === 'true';
+            setMeshcoreChannelRetryEnabledState(enabled);
+          }
+
           // Solar monitoring settings - database-only, no localStorage persistence
           if (settings.solarMonitoringEnabled !== undefined) {
             const enabled = settings.solarMonitoringEnabled === '1' || settings.solarMonitoringEnabled === 'true';
@@ -1533,6 +1557,7 @@ export const SettingsProvider: React.FC<SettingsProviderProps> = ({ children, ba
     customTilesets,
     isLoadingThemes,
     linkPreviewsEnabled,
+    meshcoreChannelRetryEnabled,
     solarMonitoringEnabled,
     solarMonitoringLatitude,
     solarMonitoringLongitude,
@@ -1581,6 +1606,7 @@ export const SettingsProvider: React.FC<SettingsProviderProps> = ({ children, ba
     updateCustomTileset,
     deleteCustomTileset,
     setLinkPreviewsEnabled,
+    setMeshcoreChannelRetryEnabled,
     setSolarMonitoringEnabled,
     setSolarMonitoringLatitude,
     setSolarMonitoringLongitude,