refactor(FN-1317): rename remaining kb references to fn

- Update executor, triage, and merger prompt strings to identify the product as "fn"
- Align branch/worktree documentation examples with fusion/fn-* naming conventions
- Rename dashboard websocket attachment guard from __kbWebSocketsAttached to __fnWebSocketsAttached
- Refresh engine tests, dashboard utility comments, and TUI header text to remove stale kb wording

packages/dashboard/app/utils/projectDetection.ts

@@ -133,7 +133,7 @@ function getDefaultScanPath(): string {
 }
 
 /**
- * Sorts detected projects by likelihood of being a kb project.
+ * Sorts detected projects by likelihood of being a fn project.
  * Projects with .fusion/fusion.db are ranked higher.
  */
 export function sortDetectedProjects(projects: DetectedProject[]): DetectedProject[] {

packages/dashboard/app/utils/worktreeGrouping.ts

@@ -8,7 +8,7 @@ export interface WorktreeGroupData {
 
 /**
  * Extract a clean display name from a worktree path.
- * e.g. ".worktrees/KB-001" → "KB-001", "/path/to/kb/kb-001" → "kb-001"
+ * e.g. ".worktrees/FN-001" → "FN-001", "/path/to/fn/fn-001" → "fn-001"
  */
 export function getWorktreeLabel(worktreePath: string): string {
   // Take the last segment of the path

packages/dashboard/src/server.ts

@@ -81,7 +81,7 @@ type DashboardExpressApp = ReturnType<typeof express> & {
   terminalWsServer?: WebSocketServer | null;
   badgeWsServer?: WebSocketServer | null;
   badgeWsManager?: WebSocketManager | null;
-  __kbWebSocketsAttached?: boolean;
+  __fnWebSocketsAttached?: boolean;
 };
 
 function shouldForceLocalhostForTests(): boolean {
@@ -433,7 +433,7 @@ export function createServer(store: TaskStore, options?: ServerOptions): ReturnT
   dashboardApp.terminalWsServer = null;
   dashboardApp.badgeWsServer = null;
   dashboardApp.badgeWsManager = null;
-  dashboardApp.__kbWebSocketsAttached = false;
+  dashboardApp.__fnWebSocketsAttached = false;
 
   const originalListen = dashboardApp.listen.bind(dashboardApp);
   dashboardApp.listen = ((...args: Parameters<typeof dashboardApp.listen>) => {
@@ -444,8 +444,8 @@ export function createServer(store: TaskStore, options?: ServerOptions): ReturnT
       aiSessionStore.stopScheduledCleanup();
     });
 
-    if (!dashboardApp.__kbWebSocketsAttached) {
-      dashboardApp.__kbWebSocketsAttached = true;
+    if (!dashboardApp.__fnWebSocketsAttached) {
+      dashboardApp.__fnWebSocketsAttached = true;
       setupTerminalWebSocket(dashboardApp, server);
       setupBadgeWebSocket(dashboardApp, server, store, options);
     }
@@ -796,7 +796,7 @@ export function setupBadgeWebSocket(
     dashboardApp.terminalWsServer = null;
     dashboardApp.badgeWsServer = null;
     dashboardApp.badgeWsManager = null;
-    dashboardApp.__kbWebSocketsAttached = false;
+    dashboardApp.__fnWebSocketsAttached = false;
   });
 }