fix(api): normalize trailing slashes — no slash on param routes

Rule: trailing slash only on collection roots (/). Any route containing
a path parameter {…} uses no trailing slash. Applies across all routers,
scripts, Makefile, and tests. Fixes 307-redirect fragility on POST/PATCH
from naive clients (curl, Codex HTTP calls).

Also adds POST /repos/{slug}/sync — runs ADR-001 consistency check with
--fix via HTTP, so non-MCP agents (Codex) can self-service DB sync without
operator intervention.

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

api/routers/domains.py

@@ -45,7 +45,7 @@ async def create_domain(
     return domain
 
 
-@router.get("/{slug}/", response_model=DomainDetail)
+@router.get("/{slug}", response_model=DomainDetail)
 async def get_domain(
     slug: str,
     session: AsyncSession = Depends(get_session),