Make storyboard editor mobile friendly

web/src/components/storyboard/ShotCard.tsx

@@ -279,7 +279,13 @@ const ShotCardInner: React.FC<ShotCardProps> = ({
               pulse={meta.pulse}
             />
             {!readOnly && (
-              <HoverActionGroup triggerSelector=".shot-card:hover" gap={0}>
+              <HoverActionGroup
+                triggerSelector=".shot-card:hover"
+                gap={0}
+                // Touch devices can't hover; keep the row actions (reorder,
+                // delete) visible there instead of hiding behind the reveal.
+                sx={{ "@media (pointer: coarse)": { opacity: 1 } }}
+              >
                 <ToolbarIconButton
                   icon={<ArrowUpwardIcon sx={{ fontSize: 16 }} />}
                   tooltip="Move up"

web/src/components/storyboard/StoryboardAgentPanel.tsx

@@ -15,6 +15,7 @@ import useGlobalChatStore from "../../stores/GlobalChatStore";
 const styles = (_theme: Theme) =>
   css({
     "&": {
+      width: "100%",
       height: "100%",
       minHeight: 0,
       display: "flex",

web/src/components/storyboard/StoryboardBoard.tsx

@@ -101,6 +101,11 @@ const styles = (theme: Theme) =>
     display: "flex",
     flexDirection: "column",
     gap: getSpacingPx(SPACING.lg),
+    // Reclaim horizontal room for shots on phones.
+    [theme.breakpoints.down("sm")]: {
+      padding: getSpacingPx(SPACING.md),
+      gap: getSpacingPx(SPACING.md)
+    },
     // Children must keep their natural height so the container scrolls;
     // otherwise the header panel gets flex-shrunk under the grid.
     "> *": { flexShrink: 0 },

web/src/components/storyboard/StoryboardSidebar.tsx

@@ -48,6 +48,12 @@ const styles = (theme: Theme) =>
     height: "100%",
     overflowY: "auto",
     borderRight: `1px solid ${theme.vars.palette.divider}`,
+    // On phones the sidebar is a full-width pane behind a segmented switcher
+    // (see StoryboardSurface), not a fixed rail beside the board.
+    [theme.breakpoints.down("sm")]: {
+      width: "100%",
+      borderRight: "none"
+    },
     padding: getSpacingPx(SPACING.md),
     display: "flex",
     flexDirection: "column",
@@ -64,7 +70,11 @@ const styles = (theme: Theme) =>
       "&:hover": { backgroundColor: theme.vars.palette.action.hover },
       "&.active": { backgroundColor: theme.vars.palette.action.selected },
       ".delete-button": { opacity: 0, transition: MOTION.opacity },
-      "&:hover .delete-button": { opacity: 1 }
+      "&:hover .delete-button": { opacity: 1 },
+      // Touch devices have no hover; keep the delete affordance reachable.
+      "@media (pointer: coarse)": {
+        ".delete-button": { opacity: 1 }
+      }
     }
   });
 

web/src/components/workspace/StoryboardSurface.tsx

@@ -1,6 +1,10 @@
 /** @jsxImportSource @emotion/react */
-import { useCallback, useEffect } from "react";
+import { useCallback, useEffect, useMemo, useState } from "react";
+import { useMediaQuery } from "@mui/material";
 import { useTheme } from "@mui/material/styles";
+import ViewListRoundedIcon from "@mui/icons-material/ViewListRounded";
+import TheatersIcon from "@mui/icons-material/Theaters";
+import AutoAwesomeIcon from "@mui/icons-material/AutoAwesome";
 import {
   useWorkspaceTabsStore,
   type WorkspaceTabMode
@@ -12,7 +16,7 @@ import { useDirectScreenplay } from "../../hooks/storyboard/useDirectScreenplay"
 import { useStoryboardServerSync } from "../../hooks/storyboard/useStoryboardServerSync";
 import { useAssembleTimeline } from "../../hooks/storyboard/useAssembleTimeline";
 import { useDocumentUndoShortcuts } from "../../hooks/useDocumentUndoShortcuts";
-import { FlexColumn } from "../ui_primitives";
+import { FlexColumn, TabGroup } from "../ui_primitives";
 import StoryboardBoard from "../storyboard/StoryboardBoard";
 import StoryboardSidebar from "../storyboard/StoryboardSidebar";
 import StoryboardQueueOverlay from "../storyboard/StoryboardQueueOverlay";
@@ -26,14 +30,34 @@ interface StoryboardSurfaceProps {
   active: boolean;
 }
 
+type MobilePane = "boards" | "board" | "assistant";
+
+const MOBILE_TABS = [
+  { value: "boards", label: "Boards", icon: <ViewListRoundedIcon /> },
+  { value: "board", label: "Board", icon: <TheatersIcon /> },
+  { value: "assistant", label: "Assistant", icon: <AutoAwesomeIcon /> }
+];
+
+const MOBILE_PANES: readonly MobilePane[] = ["boards", "board", "assistant"];
+
+const isMobilePane = (value: string): value is MobilePane =>
+  (MOBILE_PANES as readonly string[]).includes(value);
+
 /**
  * Workspace surface for a storyboard tab. `refId` is the board id. Ensures the
  * board exists in the singleton store, mounts the agent bridge (registering this
  * board under its id for the ui_storyboard_* tools) and the generation
  * subscriptions, and renders the board read-only in view mode.
+ *
+ * On wide screens the sidebar, board, and assistant sit side by side. On phones
+ * three columns don't fit, so edit mode collapses to a single pane with a
+ * segmented switcher; every pane stays mounted (toggled via `display`) so
+ * board, chat, and scroll state survive switches.
  */
 const StoryboardSurface = ({ refId, mode, active }: StoryboardSurfaceProps) => {
   const theme = useTheme();
+  const isMobile = useMediaQuery(theme.breakpoints.down("sm"));
+  const [mobilePane, setMobilePane] = useState<MobilePane>("board");
   const ensureBoard = useStoryboardStore((state) => state.ensureBoard);
   const undo = useStoryboardStore((state) => state.undo);
   const redo = useStoryboardStore((state) => state.redo);
@@ -76,6 +100,86 @@ const StoryboardSurface = ({ refId, mode, active }: StoryboardSurfaceProps) => {
     });
   }, [assemble, refId]);
 
+  const board = useMemo(
+    () => (
+      <StoryboardBoard
+        boardId={refId}
+        readOnly={mode === "view"}
+        onDirect={handleDirect}
+        directing={directing}
+        directError={error}
+        onAssemble={handleAssemble}
+        assembling={assembling}
+        assembleError={assembleError}
+      />
+    ),
+    [
+      refId,
+      mode,
+      handleDirect,
+      directing,
+      error,
+      handleAssemble,
+      assembling,
+      assembleError
+    ]
+  );
+
+  if (isMobile && mode !== "view") {
+    return (
+      <FlexColumn fullHeight sx={{ minHeight: 0, position: "relative" }}>
+        <TabGroup
+          tabs={MOBILE_TABS}
+          value={mobilePane}
+          onChange={(value) => {
+            if (isMobilePane(value)) {
+              setMobilePane(value);
+            }
+          }}
+          size="small"
+          fullWidth
+          sx={{
+            flexShrink: 0,
+            borderBottom: `1px solid ${theme.vars.palette.divider}`
+          }}
+        />
+        <div style={{ flex: 1, minHeight: 0, display: "flex" }}>
+          <div
+            style={{
+              flex: 1,
+              minWidth: 0,
+              minHeight: 0,
+              display: mobilePane === "boards" ? "flex" : "none"
+            }}
+          >
+            <StoryboardSidebar activeBoardId={refId} />
+          </div>
+          <div
+            style={{
+              flex: 1,
+              minWidth: 0,
+              minHeight: 0,
+              display: mobilePane === "board" ? "block" : "none"
+            }}
+          >
+            {board}
+          </div>
+          <div
+            style={{
+              flex: 1,
+              minWidth: 0,
+              minHeight: 0,
+              display: mobilePane === "assistant" ? "flex" : "none"
+            }}
+          >
+            <StoryboardAgentPanel boardId={refId} />
+          </div>
+        </div>
+        <StoryboardQueueOverlay boardId={refId} />
+      </FlexColumn>
+    );
+  }
+
   return (
     <div
       style={{
@@ -87,18 +191,7 @@ const StoryboardSurface = ({ refId, mode, active }: StoryboardSurfaceProps) => {
     >
       {mode !== "view" && <StoryboardSidebar activeBoardId={refId} />}
       <StoryboardQueueOverlay boardId={refId} />
-      <div style={{ flex: 1, minWidth: 0 }}>
-        <StoryboardBoard
-          boardId={refId}
-          readOnly={mode === "view"}
-          onDirect={handleDirect}
-          directing={directing}
-          directError={error}
-          onAssemble={handleAssemble}
-          assembling={assembling}
-          assembleError={assembleError}
-        />
-      </div>
+      <div style={{ flex: 1, minWidth: 0 }}>{board}</div>
       {mode !== "view" && (
         <FlexColumn
           fullHeight