feat: admin articles grouped view, live stats, + bug fixes

Admin articles list:
- Group EN/DE language variants into a single row (grouped by url_path)
- Language chips (● EN/● DE) coloured by status: green=live, amber=scheduled, blue=draft
- Inline View ↗ (live only) and Edit buttons per variant — one-click access
- Filter by language switches back to flat single-row view
- Live HTMX polling of article counts while generation runs (every 3s, self-terminates)
- Table overflow fix: card gets overflow:hidden, table wrapped in overflow-x:auto scroll div

Bug fixes:
- X-Forwarded-Proto: pass $http_x_forwarded_proto through Nginx so Quart sees https
- pipeline_routes.py: fix relative import for analytics module (from .analytics → from ..analytics)
- Scheduled articles: redirect to parent path instead of 404 when not yet published
- city-cost-de: change priority_column from population to padel_venue_count
- Quote wizard step 4: make location_status required
- Article generation: use COUNT(*) instead of 501-sentinel hack for row counts
- Makefile: pin Tailwind v4.1.18, add dev/help targets, uv run python, .PHONY

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

router/default.conf

@@ -10,6 +10,6 @@ server {
         proxy_set_header Host $host;
         proxy_set_header X-Real-IP $remote_addr;
         proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
-        proxy_set_header X-Forwarded-Proto $scheme;
+        proxy_set_header X-Forwarded-Proto $http_x_forwarded_proto;
     }
 }