feat(tui): show the pane's connection in its header (#134)

Each pane's top border now shows which backend it is browsing so a remote
pane is instantly distinguishable from the local filesystem. A remote pane
renders a full scheme://user@host:path locator (e.g. ssh://root@dietpi6:/home)
in a distinct accent color; a local pane shows just its path as before.

The pane holds only an opaque ConnectionId; a new AppState::pane_location joins
that id against the connections/saved_profiles registries at render time to
build the locator, with a graceful path-only fallback when it can't be resolved
(archive mounts, not-yet-registered connections). Adds a `remote` theme color
role (default yellow) and a `remote-pane` render scenario + snapshots.

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: zoza1982

.gitignore

@@ -44,3 +44,4 @@ lcov.info
 # WASM fixture guest build output (the built component is committed under tests/fixtures/).
 crates/cairn-plugin/tests/fixture-guest/target/
 crates/cairn-plugin/tests/fixture-guest/src/bindings.rs
+dist/

CHANGELOG.md

@@ -9,6 +9,14 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added
 
+- **Pane connection header**: each pane's top border now shows *which* backend it is browsing, so a
+  remote pane is instantly distinguishable from the local filesystem. A remote pane renders a full
+  `scheme://user@host:path` locator (e.g. `ssh://root@dietpi6:/home`, `s3://bucket:/prefix`) in a
+  distinct accent color (`remote` theme role, default yellow); a local pane shows just its path as
+  before. The identity is joined at render time from the pane's connection id against the
+  connection/profile registries, with a graceful path-only fallback when it can't be resolved (e.g.
+  inside an archive mount). Add `remote = "<color>"` under `[ui.colors]` to recolor it.
+
 - **Test a connection, pin/hide discovered entries** (RFC-0011 P6): the connection switcher
   (`Ctrl-O`) gains three new keys. `t` probes the highlighted entry's reachability without opening
   it into a pane or switching any pane — it reuses the same vetted per-scheme open path (so a real

Cargo.lock

@@ -109,15 +109,20 @@ to two transfers run at once by default — set `[transfers] concurrency = N` in
 ```
 
 Colors can be themed under `[ui.colors]` — override individual roles
-(`focused_border`, `unfocused_border`, `dir`, `error`, `status`, `selection_bg`, `selection_fg`) over
-the built-in `dark` preset, using color names or `#rrggbb`:
+(`focused_border`, `unfocused_border`, `dir`, `error`, `status`, `remote`, `selection_bg`,
+`selection_fg`) over the built-in `dark` preset, using color names or `#rrggbb`:
 
 ```toml
 [ui.colors]
 focused_border = "magenta"
 dir            = "#5fafff"
+remote         = "yellow"   # accent for a pane on a remote backend (SSH/S3/…)
 ```
 
+Each pane's top border shows which backend it is browsing: a local pane shows just its path,
+while a remote pane shows a full `scheme://user@host:path` locator (e.g.
+`ssh://root@dietpi6:/home`) in the `remote` accent color, so the two are easy to tell apart.
+
 ### Connections
 
 `Ctrl-O` opens the connection switcher — pick a backend to open in the active pane. Docker and

README.md

@@ -333,8 +333,9 @@ pub struct UiConfig {
     #[serde(default)]
     pub keybindings: BTreeMap<String, String>,
     /// Theme color overrides on top of the [`theme`](UiConfig::theme) preset: a map of role →
-    /// color. Roles are `focused_border`/`unfocused_border`/`dir`/`error`/`status`/`selection_bg`/
-    /// `selection_fg`; color *values must be strings* — names (`"cyan"`, `"bright-blue"`) or
+    /// color. Roles are `focused_border`/`unfocused_border`/`dir`/`error`/`status`/`remote`/
+    /// `selection_bg`/`selection_fg`; color *values must be strings* — names (`"cyan"`,
+    /// `"bright-blue"`) or
     /// `#rrggbb`. Unknown roles, unparseable colors, and an unknown `theme` preset are ignored with a
     /// warning (the dark preset is used).
     #[serde(default)]

crates/cairn-config/src/lib.rs

@@ -20,10 +20,10 @@ pub use state::{
     detect_file_kind, visible_connection_indices, ActiveTransfer, AppState, ArchiveFormat,
     ChoiceProvenance, ChoiceStatus, ConnectionChoice, ConnectionFormStage, ConnectionKind,
     ContentHash, DiscoverySource, FieldValue, FileKind, Listing, LogViewerId, LogViewerStatus,
-    MaskedInput, MountFrame, Overlay, PagerId, PagerMode, PagerStatus, PaneState, PendingSave,
-    PromptKind, QueuedTransfer, RemoteEditId, RemoteVersion, SessionEnd, SessionRecord,
-    ShellActionMeta, Side, SortMode, TransferId, WritebackChoice, WritebackConflictReason,
-    LOG_VIEWER_MAX_BYTES, LOG_VIEWER_MAX_LINES, PAGER_HEX_ROW_BYTES, PAGER_MAX_BYTES,
-    REMOTE_EDIT_MAX_BYTES, SESSION_OUTPUT_MAX_BYTES, SESSION_OUTPUT_MAX_LINES,
+    MaskedInput, MountFrame, Overlay, PagerId, PagerMode, PagerStatus, PaneLocation, PaneState,
+    PendingSave, PromptKind, QueuedTransfer, RemoteEditId, RemoteVersion, SessionEnd,
+    SessionRecord, ShellActionMeta, Side, SortMode, TransferId, WritebackChoice,
+    WritebackConflictReason, LOG_VIEWER_MAX_BYTES, LOG_VIEWER_MAX_LINES, PAGER_HEX_ROW_BYTES,
+    PAGER_MAX_BYTES, REMOTE_EDIT_MAX_BYTES, SESSION_OUTPUT_MAX_BYTES, SESSION_OUTPUT_MAX_LINES,
 };
 pub use update::{initial_effects, update, VAULT_PASSPHRASE_MIN_LEN};