docs: update ROADMAP, SPRINTS, TESTING to v0.50.21 (961 tests)

ROADMAP.md:
- Header: v0.49.1/700 → v0.50.21/961
- Sprint history table: 12 new rows covering v0.40 → v0.50.21 (500+ commits)
- Architecture block: updated line counts and module list

SPRINTS.md:
- Header state: v0.36/433 → v0.50.21/961
- 'Where we are now' section updated with parity status
- Historical planning content preserved as reference

TESTING.md:
- Version reference: v0.36.2 → v0.50.21
- Test count: 700 → 961 (two places)

Co-authored-by: Nathan Esquenazi <nesquena@gmail.com>

TESTING.md

@@ -1,14 +1,14 @@
 # Hermes Web UI: Browser Testing Plan
 
 > This document is for manual browser testing by you or by a Claude browser agent.
-> It covers user-facing features of the UI through Sprint 26 (v0.36.2) and later releases.
+> It covers user-facing features of the UI through v0.50.21 and later releases.
 > Each section is written as a step-by-step test procedure with expected outcomes.
 > A browser agent (e.g. Claude with Chrome access) can execute this plan directly.
 >
 > Prerequisites: SSH tunnel is active on port 8787. Open http://localhost:8787 in browser.
 > Server health check: curl http://127.0.0.1:8787/health should return {"status":"ok"}.
 >
-> Automated tests: 700 total (700 passing, 0 skipped, 0 known failures). Includes onboarding coverage for bootstrap/static wizard presence, real provider config persistence (`config.yaml` + `.env`), and the `/api/onboarding/*` backend.
+> Automated tests: 961 total (961 passing, 0 known failures). Includes onboarding coverage for bootstrap/static wizard presence, real provider config persistence (`config.yaml` + `.env`), and the `/api/onboarding/*` backend.
 > Run: `pytest tests/ -v --timeout=60`
 
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