chore: Fix all lint errors and remove unused code

- Fix 75 ESLint errors by updating eslint.config.mjs:
  - Add missing browser globals (MouseEvent, AbortController, Response, etc.)
  - Add Vite define global (__APP_VERSION__)
  - Configure @ts-nocheck to require descriptions
  - Add no-unused-vars rule for .mjs scripts

- Fix runtime bug in agent-output-modal.tsx (setOutput -> setStreamedContent)

- Remove ~120 unused variable warnings across 97 files:
  - Remove unused imports (React hooks, lucide icons, types)
  - Remove unused constants and variables
  - Remove unused function definitions
  - Prefix intentionally unused parameters with underscore

- Add descriptions to all @ts-nocheck comments (25 files)

- Clean up misc issues:
  - Remove invalid deprecation plugin comments
  - Fix eslint-disable comment placement
  - Add missing RefreshCw import in code-view.tsx

Reduces lint warnings from ~300 to 67 (all remaining are no-explicit-any)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

apps/ui/src/store/app-store.ts

@@ -1731,7 +1731,7 @@ export const useAppStore = create<AppState & AppActions>()((set, get) => ({
   },
 
   upsertAndSetCurrentProject: (path, name, theme) => {
-    const { projects, trashedProjects, currentProject, theme: globalTheme } = get();
+    const { projects, trashedProjects } = get();
     const existingProject = projects.find((p) => p.path === path);
     let project: Project;
 
@@ -2108,6 +2108,7 @@ export const useAppStore = create<AppState & AppActions>()((set, get) => ({
     let newOverrides: typeof currentOverrides;
     if (entry === null) {
       // Remove the override (use global)
+      // eslint-disable-next-line @typescript-eslint/no-unused-vars
       const { [phase]: _, ...rest } = currentOverrides;
       newOverrides = rest;
     } else {
@@ -4367,6 +4368,7 @@ export const useAppStore = create<AppState & AppActions>()((set, get) => ({
 
   clearInitScriptState: (projectPath, branch) => {
     const key = `${projectPath}::${branch}`;
+    // eslint-disable-next-line @typescript-eslint/no-unused-vars
     const { [key]: _, ...rest } = get().initScriptState;
     set({ initScriptState: rest });
   },

apps/ui/src/store/notifications-store.ts

@@ -62,7 +62,7 @@ const initialState: NotificationsState = {
 // ============================================================================
 
 export const useNotificationsStore = create<NotificationsState & NotificationsActions>(
-  (set, get) => ({
+  (set, _get) => ({
     ...initialState,
 
     // Data management

apps/ui/src/store/test-runners-store.ts

@@ -155,6 +155,7 @@ export const useTestRunnersStore = create<TestRunnersState & TestRunnersActions>
       const finishedAt = new Date().toISOString();
 
       // Remove from active sessions since it's no longer running
+      // eslint-disable-next-line @typescript-eslint/no-unused-vars
       const { [session.worktreePath]: _, ...remainingActive } = state.activeSessionByWorktree;
 
       return {