docs(08-04/05/06): add plan summaries — wave 2 backend decomposition complete

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

.planning/phases/08-stack-upgrade-backend-decomposition/08-06-SUMMARY.md

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+# Plan 08-06 Summary — Auth API Decomposition
+
+**Status:** Complete  
+**Requirements:** CODE-03, CODE-08, CR-01, CR-02, CR-03  
+**Date:** 2026-06-12
+
+## What Was Done
+
+- Created `backend/api/auth/` package: `shared.py`, `tokens.py`, `totp.py`, `password.py`, `__init__.py`
+- `limiter` defined in `shared.py`, re-exported from `__init__.py` — `from api.auth import limiter` unchanged
+- CR-01 (`change_password`), CR-02 (`enable_totp`), CR-03 (`disable_totp`) — `revoke_all_refresh_tokens(skip_token_hash=skip_hash)` preserved verbatim
+- ES256, JTI, fgp token hardening preserved verbatim in `tokens.py`
+- Deleted `backend/api/auth.py` monolith; zero test files modified
+
+## Test Results
+
+- `tests/test_auth.py` CR tests: PASSED (all 3)
+- Auth + rate-limit + TOTP + replay + headers: 52 passed
+- `app.state.limiter is api.auth.limiter` identity: confirmed
+- Full suite: 405 passed