feat(FN-1433): wire prompt overrides into mission interview service

- Import resolvePrompt and PromptOverrideMap from @fusion/core
- Add promptOverrides parameter to all agent creation paths:
  - createMissionInterviewSession
  - submitMissionInterviewResponse
  - retryMissionInterviewSession
  - initializeAgent
  - createMissionInterviewAgent
  - ensureMissionInterviewAgent
- Use resolvePrompt('planning-system', promptOverrides) for effective prompt
- Fall back to MISSION_INTERVIEW_SYSTEM_PROMPT when override absent
- Update module docs to reflect prompt override behavior

packages/dashboard/app/components/TaskCard.tsx

@@ -497,7 +497,7 @@ function TaskCardComponent({
     task.column,
     task.mergeDetails?.commitSha,
     projectId,
-    { enabled: isInViewport },
+    { enabled: isInViewport, worktree: task.worktree },
   );
 
   // Get fresh batch data if available
@@ -910,17 +910,24 @@ function TaskCardComponent({
           </>
         );
       })()}
-      {task.worktree && (task.column === "in-progress" || task.column === "in-review") && (
-        <button
-          type="button"
-          className="card-session-files"
-          onClick={handleOpenFiles}
-          disabled={!onOpenDetailWithTab}
-        >
-          <Folder size={12} />
-          <span>View files</span>
-        </button>
-      )}
+      {task.worktree && (task.column === "in-progress" || task.column === "in-review") && (() => {
+        const activeCount = diffStats?.filesChanged;
+        return (
+          <button
+            type="button"
+            className="card-session-files"
+            onClick={handleOpenFiles}
+            disabled={!onOpenDetailWithTab}
+          >
+            <Folder size={12} />
+            <span>
+              {activeCount != null && activeCount > 0
+                ? `${activeCount} ${activeCount === 1 ? "file" : "files"} changed`
+                : "View files"}
+            </span>
+          </button>
+        );
+      })()}
       {task.column === "done" && (() => {
         // Prefer diff stats from the same endpoint the modal uses so the
         // count is always consistent with the Changes tab.

packages/dashboard/app/components/__tests__/TaskCard.test.tsx

@@ -3227,13 +3227,54 @@ describe("TaskCard singular/plural file count", () => {
     mockUseTaskDiffStats.mockReturnValue({ stats: null, loading: false });
   });
 
-  it("shows a static files action for in-progress worktrees without fetching file counts", () => {
+  it("shows changed-file counts for in-progress worktrees", () => {
     const task = makeTask({
       column: "in-progress",
       worktree: "/repo/.worktrees/fn-099",
       status: "executing",
     });
-    mockUseSessionFiles.mockReturnValue({ files: ["src/a.ts"], loading: false });
+    mockUseTaskDiffStats.mockReturnValue({ stats: { filesChanged: 3, additions: 10, deletions: 2 }, loading: false });
+
+    render(
+      <TaskCard
+        task={task}
+        onOpenDetail={vi.fn()}
+        addToast={noopToast}
+      />
+    );
+
+    expect(screen.getByText("3 files changed")).toBeInTheDocument();
+    expect(screen.queryByText("View files")).not.toBeInTheDocument();
+    expect(screen.queryByText("Checking files…")).not.toBeInTheDocument();
+  });
+
+  it("shows changed-file counts for in-review worktrees", () => {
+    const task = makeTask({
+      column: "in-review",
+      worktree: "/repo/.worktrees/fn-099",
+      status: "reviewing",
+    });
+    mockUseTaskDiffStats.mockReturnValue({ stats: { filesChanged: 2, additions: 7, deletions: 1 }, loading: false });
+
+    render(
+      <TaskCard
+        task={task}
+        onOpenDetail={vi.fn()}
+        addToast={noopToast}
+      />
+    );
+
+    expect(screen.getByText("2 files changed")).toBeInTheDocument();
+    expect(screen.queryByText("View files")).not.toBeInTheDocument();
+  });
+
+  it("falls back to View files for in-progress worktrees without a positive diff count", () => {
+    const task = makeTask({
+      column: "in-progress",
+      worktree: "/repo/.worktrees/fn-099",
+      status: "executing",
+    });
+    mockUseTaskDiffStats.mockReturnValue({ stats: { filesChanged: 0, additions: 0, deletions: 0 }, loading: false });
 
     render(
       <TaskCard
@@ -3245,27 +3286,6 @@ describe("TaskCard singular/plural file count", () => {
 
     expect(screen.getByText("View files")).toBeInTheDocument();
     expect(screen.queryByText(/files? changed/)).not.toBeInTheDocument();
-    expect(screen.queryByText("Checking files…")).not.toBeInTheDocument();
-  });
-
-  it("does not use session file counts for in-progress worktree cards", () => {
-    const task = makeTask({
-      column: "in-progress",
-      worktree: "/repo/.worktrees/fn-099",
-      status: "executing",
-    });
-    mockUseSessionFiles.mockReturnValue({ files: ["src/a.ts", "src/b.ts"], loading: false });
-
-    render(
-      <TaskCard
-        task={task}
-        onOpenDetail={vi.fn()}
-        addToast={noopToast}
-      />
-    );
-
-    expect(screen.getByText("View files")).toBeInTheDocument();
-    expect(screen.queryByText("2 files changed")).not.toBeInTheDocument();
   });
 
   it("displays '1 file changed' (singular) for done column with displayCount=1 via diffStats", () => {