docs: add missing content from summary.md (API reference, Android app, file structure, LLM internals)

- docs/api-reference.md: complete REST API endpoint reference (~60+ routes)
- docs/android-app.md: Flutter companion app stack, architecture, feature status
- docs/architecture.md: detailed file-by-file reference for all backend services and frontend components
- docs/features.md: LLM pipeline internals (intent routing, tool loop, duplicate guards, image search, research pipeline), roadmap
- docs/development.md: full migration chain (0001–0026) with naming and caveats
- README.md: link to new api-reference and android-app docs

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

docs/android-app.md

@@ -0,0 +1,73 @@
+# Android Companion App
+
+The Android companion app lives in a separate repository at `/home/bvandeusen/Nextcloud/Projects/fabled_app`.
+
+## Stack
+
+- Flutter + Dart
+- Riverpod (state management)
+- GoRouter (navigation)
+- Dio (HTTP client)
+- PersistCookieJar (session persistence)
+- SSE streaming via `fetch` + `ReadableStream` bridge
+
+## Architecture
+
+```
+lib/
+  app.dart                          # GoRouter + _Shell + _QuickCaptureBar
+  core/constants.dart               # Routes.*
+  data/
+    models/                         # note.dart, task.dart, project.dart
+    api/                            # notes_api.dart, tasks_api.dart, projects_api.dart
+    repositories/                   # notes, tasks, projects repositories
+  providers/
+    api_client_provider.dart        # all API + repository providers
+    notes_provider.dart             # NotesNotifier
+    tasks_provider.dart             # TasksNotifier
+    projects_provider.dart          # ProjectsNotifier
+  screens/
+    notes/note_edit_screen.dart     # chip tag input + ProjectSelector
+    tasks/task_edit_screen.dart     # ProjectSelector
+    projects/project_list_screen.dart
+  widgets/
+    project_selector.dart           # reusable DropdownButtonFormField
+```
+
+## Navigation
+
+4-tab shell (Notes · Tasks · Projects · Chat):
+- Phone: bottom `NavigationBar`
+- Tablet/landscape: `NavigationRail`
+
+Quick Capture bar persists across all tabs. Settings accessible from top-right icon.
+
+## Feature Status
+
+| Feature | Status | Notes |
+|---------|--------|-------|
+| Notes CRUD | ✅ | Tags chip input; project selector in editor |
+| Tasks CRUD | ✅ | Project selector in editor |
+| Projects list | ✅ | Active/archived sections; long-press status change; create dialog |
+| Chat + SSE | ✅ | Full streaming |
+| Quick Capture | ✅ | Offline queue with retry |
+| Tags | ✅ | Chip input in NoteEditScreen; typed as `List<String>` |
+| Project assignment | ✅ | `ProjectSelector` dropdown in Note + Task editors |
+| Milestones | ❌ deferred | Too granular for mobile; web UI handles it |
+| Push notifications | ❌ incompatible | Backend uses browser VAPID; Flutter needs FCM/APNs — separate implementation required |
+| CalDAV settings | ❌ intentional | Server-side config only; not exposed in mobile app |
+
+## API Compatibility Notes
+
+- `GET /api/projects/:id` returns a flat JSON object (not `{project: ...}` wrapper); includes `summary` field.
+- `POST /api/projects` returns the project dict directly (201).
+- `PATCH /api/projects/:id` returns the updated project dict.
+- Task body field is `body` (not `description`) — the app maps `description` → `body` on serialize.
+
+## Self-Update
+
+The app supports self-update via the Forgejo release API (`update_provider.dart`). It checks the latest release tag and prompts the user to download and install a new APK when one is available.
+
+## CI
+
+Builds are triggered from the Forgejo Actions pipeline in the `fabled_app` repository. The APK is attached to the release as a downloadable artifact.