feat: web push notifications (VAPID)

- push_utils.py: subscription storage + send helper (auto-prunes 410 endpoints)
- routers/push.py: GET /api/push/vapid-key (public), POST/DELETE /api/push/subscribe
- sw.js: push event listener shows notification; notificationclick focuses/opens tab
- app.js: subscribe/unsubscribe flow + "Enable notifications" toggle in settings dropdown
- tools/notify.py: web_push orchestrator tool (user-level, no admin required)
- VAPID keys in .env; pywebpush added to requirements.txt

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

documentation/TODO__Agents.md

@@ -89,9 +89,9 @@ See `ARCH__Intelligence_Layer.md` for full design.
 - [x] Tool: `ae_journal_entry_disable` — soft-delete via enable=false — 2026-04-28
 - [x] Tool: `ae_journal_entry_append` — read→append timestamped section→write (running logs) — 2026-04-28
 - [x] Tool: `ae_journal_entry_prepend` — read→prepend timestamped section→write (newest-first logs) — 2026-04-28
-- [ ] Import script: walk a markdown directory, chunk by H2 section, create entries
-- [ ] Target: markdown files from `~/DgrZone_Nextcloud/` and `~/OSIT_Nextcloud/`
-- [ ] Tag strategy: source path, date, topic tags from frontmatter or filename
+- [x] Import script: walk a markdown directory, chunk by H2 section, create entries — 2026-05-05
+- [x] Target: markdown files from `~/DgrZone_Nextcloud/` and `~/OSIT_Nextcloud/` — 2026-05-05
+- [x] Tag strategy: source path, topic tags from path components — 2026-05-05
 
 ---
 
@@ -116,8 +116,8 @@ Read before finalising either design.
 ### [Backend] API usage / cost tracking
 Multi-user setup with real Gemini/Claude API costs. Track per-user token consumption
 so Scott can see who's spending what.
-- [ ] Count input + output tokens per `/chat` and `/orchestrate` call (all backends return usage)
-- [ ] Append to `home/{user}/usage.json` — daily buckets, per-model breakdown
+- [x] Count input + output tokens — local backend (OpenAI `usage` field) + Gemini API (`usage_metadata`) — 2026-05-05
+- [x] Append to `home/{user}/usage.json` — daily buckets, per-model breakdown — 2026-05-05
 - [ ] Expose via `/api/usage` endpoint; add a summary row to the Settings page
 - [ ] Optional: soft spending limit with a warning toast when exceeded