fix(ci): pin test deps to prevent breaking updates + restore architecture_brief

Root cause: pytest/pytest-asyncio/aiosqlite minimum version pins (>=X)
allowed pip to install latest versions that may have breaking changes.
The first CI run (a319feb) passed because it ran before the update;
all subsequent runs failed with exit code 4 (collection error).

Fix: Pin upper bounds on test dependencies:
- pytest>=8.0.0,<8.4.0
- pytest-asyncio>=0.24.0,<0.26.0
- aiosqlite>=0.20.0,<0.21.0
- httpx>=0.28.1,<0.29.0

Also restore architecture_brief.py to CI pipeline (was removed
during debugging, now restored since issue was deps not script).

https://claude.ai/code/session_01W1rJthWDkasijTdXCfxVHs

.github/workflows/dealix-ci.yml

@@ -25,6 +25,9 @@ jobs:
       - name: Install dependencies
         run: |
           pip install -r requirements.txt -r requirements-dev.txt
+      - name: Architecture Brief (governance validation)
+        working-directory: salesflow-saas
+        run: python scripts/architecture_brief.py
       - name: Pytest (full suite + launch scenarios)
         env:
           DATABASE_URL: sqlite+aiosqlite:///./ci_dealix.db

salesflow-saas/backend/requirements-dev.txt

@@ -1,4 +1,5 @@
 # Dev / CI — not required in production images
-pytest>=8.0.0
-pytest-asyncio>=0.24.0
-aiosqlite>=0.20.0
+pytest>=8.0.0,<8.4.0
+pytest-asyncio>=0.24.0,<0.26.0
+aiosqlite>=0.20.0,<0.21.0
+httpx>=0.28.1,<0.29.0