docs(38-02): complete admin tag management client UI plan

- Add 38-02-SUMMARY.md
- Advance STATE.md to 38-02 complete
- Mark 38-02-PLAN.md complete in ROADMAP.md

.planning/ROADMAP.md

@@ -280,7 +280,7 @@ Plans:
 
 Plans:
 - [x] 38-01-PLAN.md — Schema migration (parentId), service layer (CRUD + cycle detection), API routes, tests
-- [ ] 38-02-PLAN.md — Client hooks, tag list page (tree view + quick-add + search), edit page (rename/reparent/delete), sidebar activation
+- [x] 38-02-PLAN.md — Client hooks, tag list page (tree view + quick-add + search), edit page (rename/reparent/delete), sidebar activation
 
 **UI hint**: yes
 

.planning/STATE.md

@@ -3,8 +3,8 @@ gsd_state_version: 1.0
 milestone: v2.4
 milestone_name: Admin Foundation
 status: executing
-stopped_at: Completed 35-03-PLAN.md — FIX-05 (cursor-pointer audit) resolved
+stopped_at: Completed 38-02-PLAN.md — admin tag management client UI
-last_updated: "2026-04-19T20:29:07.741Z"
+last_updated: "2026-04-19T20:32:22Z"
 last_activity: 2026-04-19
 progress:
   total_phases: 20
@@ -30,7 +30,7 @@ Plan: 2 of 2
 Status: Ready to execute
 Last activity: 2026-04-19
 
-Progress: [████████░░] 94%
+Progress: [█████████░] 97%
 
 ## Performance Metrics
 
@@ -110,6 +110,6 @@ Items carried forward from v2.3:
 
 ## Session Continuity
 
-Last session: 2026-04-19T20:29:07.738Z
+Last session: 2026-04-19T20:32:22Z
-Stopped at: Completed 35-03-PLAN.md — FIX-05 (cursor-pointer audit) resolved
+Stopped at: Completed 38-02-PLAN.md — admin tag management client UI
 Resume file: None

.planning/phases/38-admin-tag-management/38-02-SUMMARY.md

@@ -0,0 +1,94 @@
+---
+phase: 38-admin-tag-management
+plan: "02"
+subsystem: client
+tags: [admin, tags, react-query, tree-view, crud]
+dependency_graph:
+  requires: ["38-01"]
+  provides: ["admin-tag-ui"]
+  affects: ["src/client/routes/admin/", "src/client/hooks/"]
+tech_stack:
+  added: []
+  patterns:
+    - collapsible tree view with buildTree/flattenTree/filterTree utilities
+    - dual React Query key invalidation (admin-tags + tags)
+    - cycle-safe parent picker via getDescendantIds client-side filtering
+    - impact-aware delete confirmation (item count + child count)
+key_files:
+  created:
+    - src/client/hooks/useAdminTags.ts
+    - src/client/routes/admin/tags.tsx
+    - src/client/routes/admin/tags.$tagId.tsx
+  modified:
+    - src/client/routes/admin.tsx
+decisions:
+  - "buildTree/flattenTree/filterTree co-located in tags.tsx — pure JS utilities, no separate lib file needed"
+  - "Dual query key invalidation on all tag mutations keeps public tags cache fresh alongside admin cache"
+  - "getDescendantIds used client-side for parent picker filtering — server validates cycles authoritatively"
+metrics:
+  duration: "2m"
+  completed: "2026-04-19"
+  tasks_completed: 2
+  tasks_total: 2
+  files_changed: 4
+---
+
+# Phase 38 Plan 02: Admin Tag Management Client UI Summary
+
+React Query hooks, collapsible tree list page, edit page with cycle-safe reparent and impact-aware delete confirmation, and Tags sidebar link activated in the admin panel.
+
+## Tasks Completed
+
+| # | Name | Commit | Files |
+|---|------|--------|-------|
+| 1 | Client hooks + tag list page with tree view and quick-add | 1f8b85d | useAdminTags.ts, admin/tags.tsx |
+| 2 | Tag edit page with rename, reparent, delete + sidebar link activation | 0571ee4 | admin/tags.$tagId.tsx, admin.tsx |
+
+## What Was Built
+
+### `src/client/hooks/useAdminTags.ts`
+
+Five React Query hooks: `useAdminTags` (list), `useAdminTag` (single with 404 retry suppression), `useCreateAdminTag`, `useUpdateAdminTag`, `useDeleteAdminTag`. All mutations invalidate both `["admin-tags"]` and `["tags"]` to keep the public tag cache fresh.
+
+### `src/client/routes/admin/tags.tsx`
+
+Tag list page at `/admin/tags` with:
+- `buildTree` — builds hierarchical tree from flat array with self-referential parent links
+- `flattenTree` — depth-first flatten respecting the `expanded` Set for show/hide
+- `filterTree` — recursive filter that preserves parent rows when descendants match
+- Collapsible chevron-based tree rows with 20px-per-depth indentation
+- Quick-add inline form with name input, parent picker (`No parent (top-level)` default), and "Add Tag" button
+- Search input filtering tree in-place
+- Skeleton loading, error state, two empty states (no tags / no search results)
+
+### `src/client/routes/admin/tags.$tagId.tsx`
+
+Tag edit page at `/admin/tags/$tagId` with:
+- `getDescendantIds` — recursively collects all descendant IDs to exclude from parent picker (client-side cycle prevention)
+- `getDeleteConfirmText` — builds contextual confirmation: item count warning + child count warning + "This cannot be undone."
+- Name rename field and cycle-safe parent picker (`parentOptions` excludes self + all descendants)
+- Delete confirmation modal with impact-aware body text per D-13/D-14
+- Actions row: Delete Tag (left, destructive) / Save Changes (right, primary)
+
+### `src/client/routes/admin.tsx`
+
+Replaced the disabled `<div cursor-not-allowed>` Tags entry with an active `<Link to="/admin/tags">` following the Items link pattern. "Soon" badge removed.
+
+## Deviations from Plan
+
+None — plan executed exactly as written.
+
+## Threat Surface Scan
+
+No new network endpoints, auth paths, or schema changes introduced (client-only plan). T-38-05 admin shell guard already present in admin.tsx. T-38-06 client-side cycle prevention implemented as UX layer; server validates authoritatively.
+
+## Self-Check: PASSED
+
+- src/client/hooks/useAdminTags.ts: FOUND
+- src/client/routes/admin/tags.tsx: FOUND
+- src/client/routes/admin/tags.$tagId.tsx: FOUND
+- src/client/routes/admin.tsx: modified (contains `to="/admin/tags"`, no `cursor-not-allowed`)
+- Commit 1f8b85d: FOUND
+- Commit 0571ee4: FOUND
+- Build: PASSED (✓ built in 964ms)
+- Tests: PASSED (500 pass, 0 fail)