feat(analytics): add Python NeighborhoodScore service + NestJS HTTP proxy (TEC-2756)

- libs/ai-services: new POST /neighborhood/score router computing weighted
  6-axis livability score from per-category POI counts; algorithm versioned
  for future iteration (sigmoid curves, percentile thresholds).
- apps/api: HttpNeighborhoodScoreService proxies to Python first, falls back
  to PrismaNeighborhoodScoreService when AI service unavailable. Mirrors the
  HttpAVMService pattern. Existing GET /analytics/neighborhoods/:district/score
  endpoint and CQRS handler now flow through the proxy.
- AnalyticsModule binds Http variant by default, retains Prisma variant as
  injectable fallback.
- Tests: 5 pytest cases for Python heuristic, 4 vitest cases for HTTP proxy
  fallback behaviour.

Co-Authored-By: Paperclip <noreply@paperclip.ing>

libs/ai-services/app/routers/neighborhood.py

@@ -0,0 +1,12 @@
+from fastapi import APIRouter
+
+from app.models.neighborhood import NeighborhoodScoreRequest, NeighborhoodScoreResponse
+from app.services.neighborhood_service import neighborhood_score_service
+
+router = APIRouter(prefix="/neighborhood", tags=["Neighborhood"])
+
+
+@router.post("/score", response_model=NeighborhoodScoreResponse)
+def score(req: NeighborhoodScoreRequest) -> NeighborhoodScoreResponse:
+    """Compute weighted 0-100 livability score from per-category POI counts."""
+    return neighborhood_score_service.score(req)