Fix rate limits, concurrency control, copy button

- DATA-BACKED RATE LIMITS:
  * Reduce global rate limit from 10,000/min to 100/min
  * Add PDF conversion rate limits: 10/min free, 30/min pro
  * Set recovery rate limit to 3/hour (was 5/hour)
  * Add concurrency limiter: max 3 simultaneous PDFs, queue rest
  * Return 429 if queue > 10

- BUG-025: Fix copy button functionality
  * Improve fallback handling for execCommand
  * Add better error handling and user feedback
  * Fix secure context detection

- Add concurrency monitoring endpoint /v1/concurrency

sessions.md

@@ -0,0 +1,37 @@
+# DocFast Sessions Log
+
+## 2026-02-14 22:14 UTC — Deployment + QA Session
+
+**Trigger:** Latest code changes (Swagger UI, key recovery UI, email change) were not deployed despite being in the working tree.
+
+**Actions:**
+1. SSH'd into server (167.235.156.214)
+2. Found uncommitted changes in working tree (email change UI, Swagger UI, key recovery link)
+3. Committed all changes: `d859e9f` — "feat: email change UI, Swagger UI improvements, key recovery link on landing page"
+4. Pushed to Forgejo (openclawd/docfast)
+5. Rebuilt container with `docker compose build --no-cache`
+6. Restarted: `docker compose up -d`
+7. Verified server healthy: 15-page browser pool, version 0.2.1
+
+**QA Results:**
+| Test | Result |
+|------|--------|
+| Landing page loads | ✅ 200 OK |
+| Key recovery link on landing | ✅ Present |
+| Email change link in footer | ✅ Present |
+| Swagger UI at /docs | ✅ 200 OK |
+| Signup endpoint | ✅ Works (verification_required) |
+| Key recovery endpoint | ✅ Works (recovery_sent) |
+| Email change backend | ❌ NOT IMPLEMENTED (BUG-030) |
+| HTML→PDF conversion | ✅ Valid PDF |
+| Markdown→PDF conversion | ✅ Valid PDF |
+| URL→PDF conversion | ✅ Valid PDF |
+| Health endpoint | ✅ Pool: 15 pages, 0 active |
+| Browser pool | ✅ 1 browser × 15 pages |
+
+**Bugs Found:**
+- BUG-030: Email change backend not implemented (frontend-only)
+- BUG-031: Stray `\001@` file in repo
+- BUG-032: Swagger UI needs browser QA for full verification
+
+**Note:** Browser-based QA not available (openclaw browser service unreachable). Console error check, mobile responsive test, and full Swagger UI render verification deferred.