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+---
+phase: 04-folders-sharing-quotas-document-ux
+plan: "08"
+subsystem: frontend-data-layer
+tags: [api-client, pinia, vue-router, folders, shares, preferences, search]
+dependency_graph:
+  requires: ["04-07"]
+  provides: ["frontend-data-contracts-for-04-09"]
+  affects: ["frontend/src/api/client.js", "frontend/src/stores/folders.js", "frontend/src/stores/documents.js", "frontend/src/router/index.js"]
+tech_stack:
+  added: []
+  patterns: ["Pinia Composition API store", "debounced watcher without lodash", "lazy route imports"]
+key_files:
+  created:
+    - frontend/src/stores/folders.js
+  modified:
+    - frontend/src/api/client.js
+    - frontend/src/stores/documents.js
+    - frontend/src/router/index.js
+decisions:
+  - "listDocuments extended in-place (not replaced) to preserve backward compatibility with existing callers"
+  - "getDocumentContentUrl returns a plain string (no fetch) for use as iframe src or window.open target"
+  - "searchQuery watcher enforces 2-char minimum before API call — shorter inputs restore full list without hitting backend"
+  - "New routes use same implicit beforeEach auth guard as existing routes (check !meta.public && !accessToken)"
+metrics:
+  duration: "12 minutes"
+  completed: "2026-05-25"
+  tasks_completed: 2
+  tasks_total: 2
+  files_changed: 4
+---
+
+# Phase 4 Plan 08: Frontend Data Layer Summary
+
+**One-liner:** Wired all Phase 4 backend endpoints to the frontend via 13 new API client functions, a new useFoldersStore (Pinia Composition API), extended useDocumentsStore with folder/search/sort/share state, and two new authenticated routes.
+
+## Tasks Completed
+
+| # | Task | Commit | Files |
+|---|------|--------|-------|
+| 1 | Add Phase 4 API functions to client.js and create folders store | 5417f26 | frontend/src/api/client.js, frontend/src/stores/folders.js |
+| 2 | Extend documents store with folder/search/share actions + add Vue Router routes | 5417f26 | frontend/src/stores/documents.js, frontend/src/router/index.js |
+
+## What Was Built
+
+### API Client Extensions (frontend/src/api/client.js)
+
+**`listDocuments` updated** to accept `folderId`, `q`, `sort`, `order` params — passed via `URLSearchParams` when non-null/non-empty.
+
+**13 new functions added:**
+
+| Group | Functions |
+|-------|-----------|
+| Folders | `listFolders`, `createFolder`, `getFolder`, `renameFolder`, `deleteFolder`, `moveDocument` |
+| Shares | `createShare`, `listShares`, `deleteShare`, `getSharedWithMe` |
+| Preferences | `getMyPreferences`, `updateMyPreferences` |
+| Proxy URL | `getDocumentContentUrl` |
+
+### Folders Store (frontend/src/stores/folders.js)
+
+New Pinia Composition API store (`useFoldersStore`) following the exact `useTopicsStore` pattern:
+- State: `folders`, `currentFolderId`, `breadcrumb`, `loading`, `error`
+- Actions: `fetchFolders`, `createFolder`, `renameFolder`, `deleteFolder`, `navigateTo`
+- `navigateTo` fetches folder detail for breadcrumb population; handles null (root) cleanly
+
+### Documents Store Extensions (frontend/src/stores/documents.js)
+
+- Added `watch` import from 'vue'
+- New state refs: `currentFolderId`, `searchQuery`, `sortField`, `sortOrder`
+- `fetchDocuments` extended to accept and pass `folderId`, `q`, `sort`, `order` to `api.listDocuments`
+- Debounced `searchQuery` watcher: 300ms delay, 2-char minimum (T-04-08-03 mitigated)
+- New share actions: `shareDocument`, `revokeShare`, `listShares`
+- Return statement extended with all new state and actions
+
+### Router Routes (frontend/src/router/index.js)
+
+Two new lazy-loaded authenticated routes appended:
+- `/folders/:folderId` → `FolderView.vue` (named `folder`)
+- `/shared` → `SharedView.vue` (named `shared`)
+
+Both use `meta: { requiresAuth: true }` and are guarded by the existing `beforeEach` hook.
+
+## Deviations from Plan
+
+None — plan executed exactly as written.
+
+## Threat Mitigations Applied
+
+| Threat | Mitigation |
+|--------|-----------|
+| T-04-08-01 — unguarded routes | Both new routes have `meta: { requiresAuth: true }` |
+| T-04-08-03 — premature search | `searchQuery` watcher checks `newVal.length < 2` before firing API call |
+
+## Known Stubs
+
+None. This plan creates data layer only — no UI components with rendering stubs.
+
+## Self-Check: PASSED
+
+- `frontend/src/api/client.js` — FOUND, 45 export functions (13 new)
+- `frontend/src/stores/folders.js` — FOUND, exports `useFoldersStore`
+- `frontend/src/stores/documents.js` — FOUND, contains all new refs and actions
+- `frontend/src/router/index.js` — FOUND, contains `/folders/:folderId` and `/shared` routes
+- Commit `5417f26` — FOUND in git log