merge: integrate main restructuring into dev

- Resolve 57 merge conflicts from codebase restructure
- Port dev feature code to new directory structure:
  * Update import paths to use @/ aliases
  * Add backward-compatible API signatures (createInstance, startInstance, deleteInstance)
  * Add missing type exports (ProjectWithRepos, InstanceHealth, Branch, BranchesResponse)
  * Extend Session and GitRepository types for dev features
  * Extend TerminalComponent props for mobile terminal wrapper
  * Add missing icon names (bell, drag, undo)

Quality gates: tsc pass (0 errors), build pass, 127/131 tests pass
(4 pre-existing failures unrelated to merge)

apps/web/tsconfig.json

@@ -10,7 +10,11 @@
     "skipLibCheck": true,
     "resolveJsonModule": true,
     "isolatedModules": true,
-    "types": ["vite/client"]
+    "types": ["vite/client"],
+    "baseUrl": ".",
+    "paths": {
+      "@/*": ["src/*"]
+    }
   },
   "include": ["src"],
   "exclude": ["**/*.test.ts", "**/*.test.tsx"]