fix: resolve merge conflicts and clean up expand project feature

Post-merge fixes for PR #36 (expand-project-with-ai):

- Fix syntax error in App.tsx Escape handler (missing `} else`)
- Fix missing closing brace in types.ts FeatureBulkCreateResponse
- Remove unused exception variables flagged by ruff (F841)
- Make nav buttons minimalist: remove text labels, keep icons + shortcuts
  - "Add Feature" → icon + N shortcut, tooltip "Add new feature"
  - "Expand" → icon + E shortcut, tooltip "Expand project with AI"

All checks pass: ruff, security tests, ESLint, TypeScript build.

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

ui/src/lib/types.ts

@@ -329,6 +329,9 @@ export interface FeatureBulkCreate {
 export interface FeatureBulkCreateResponse {
   created: number
   features: Feature[]
+}
+
+// ============================================================================
 // Settings Types
 // ============================================================================