§22 S6: release v0.45.0 — two-project/multi-collection test + §20.4 changelog

The release wrap for the S6 scope shipped this slice (SPEC merge, per-collection
enabled_models, type-driven entry noun).

- test_s6_two_project_multicollection.py: an integrative pass proving the new
  per-collection knobs (§22.12 enabled_models, §22.4a noun) resolve independently
  per collection across two projects with no cross-project/-collection bleed.
- CHANGELOG.md 0.45.0: the §20.4 entry + upgrade-steps (migration 031 is
  additive + automatic; per-collection enabled_models and typed collections are
  optional). Notes the two OPEN S6 items carried to a follow-up slice (per-type
  surfaces; request-to-join + cross-collection inbox).
- VERSION + frontend/package.json → 0.45.0.

Gate: backend 530 passed, frontend 30 passed, build green.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

frontend/package.json

@@ -1,7 +1,7 @@
 {
   "name": "rfc-app-frontend",
   "private": true,
-  "version": "0.44.0",
+  "version": "0.45.0",
   "type": "module",
   "scripts": {
     "dev": "vite",