Map backgrounds (aerial/osm/dark/light), bbox zoom, world locator, kometa YAML endpoint

posters_service:
- BackgroundStyle enum + tile stitcher for race posters
  (Esri aerial / OSM Carto / CartoDB dark / CartoDB light / none)
- _resolve_circuit_geo: GeoJSON bbox centre + auto-zoom (no hand tuning),
  falls back to Jolpica lat/lon + f1-locations.json zoom
- _draw_track_projected: project the layout's GeoJSON points into the
  same window as the tile background, so the white outline aligns with
  the actual track (the hand-drawn SVGs had arbitrary orientations)
- _render_world_locator: 140x140 CartoDB Dark inset at zoom 5 with a
  red marker pinning the circuit on the continent
- _race_dark_overlay: dimming so the heading + footer stay legible
  against any underlying tiles
- render_kometa_metadata: emits a Kometa-compatible YAML covering
  every season 1950..current+1 with per-show + per-round url_poster

cdn-api:
- GET /posters/race/{name}/{year}.png supports ?bg= query param
- GET /kometa/formula-1-metadata.yml serves the generated config so
  Kometa pulls it via metadata_files.url (auto-updates with schedule)

cdn-api.py

@@ -1,5 +1,5 @@
 from fastapi import FastAPI, HTTPException, Response
-from fastapi.responses import FileResponse, Response as FastAPIResponse
+from fastapi.responses import FileResponse, Response as FastAPIResponse, PlainTextResponse
 from fastapi.middleware.cors import CORSMiddleware
 from pathlib import Path
 import logging
@@ -7,7 +7,7 @@ import logging
 # Import our CircuitService
 from circuits_service import CircuitService, Format
 from ergast_service import ErgastService
-from posters_service import PostersService
+from posters_service import PostersService, BackgroundStyle
 from models.track_layout import TrackLayout
 
 # Initialize FastAPI app
@@ -71,9 +71,15 @@ async def root():
 
 
 @app.get("/posters/race/{grand_prix_name}/{season}.png")
-async def get_race_poster(grand_prix_name: str, season: int):
-    """Plex-ready 1000x1500 race poster (PNG). Cached on disk."""
-    png = posters_service.render_race_poster(grand_prix_name, season)
+async def get_race_poster(grand_prix_name: str, season: int, bg: BackgroundStyle = BackgroundStyle.AERIAL):
+    """Plex-ready 1000x1500 race poster (PNG). Cached on disk per (race, bg).
+
+    `?bg=` selects the backdrop:
+      - aerial (default) — Esri World Imagery satellite at the circuit's coords
+      - osm              — OpenStreetMap Carto street-map at the circuit's coords
+      - none             — plain black background (skip tile fetch)
+    """
+    png = posters_service.render_race_poster(grand_prix_name, season, bg=bg)
     if not png:
         raise HTTPException(status_code=404, detail=f"No poster available for {grand_prix_name} {season}")
     return FastAPIResponse(
@@ -93,6 +99,28 @@ async def get_season_poster(season: int):
         headers={"Cache-Control": "public, max-age=31536000"},
     )
 
+
+@app.get("/kometa/formula-1-metadata.yml")
+async def get_kometa_metadata():
+    """Generate a Kometa-compatible metadata YAML for the Formula 1 library.
+
+    One entry per F1 season from 1950..current+1. Each entry:
+      - uses Kometa's f1_season builder for round/episode names
+      - sets url_poster on the show (per-season hero from files-api)
+      - sets url_poster on each Plex 'season' (== each F1 round) from the
+        f1-circuits race poster endpoint
+
+    Kometa harmlessly skips shows / seasons that don't exist in the Plex
+    library, so we can emit the full schedule and let Kometa do the matching.
+    """
+    yaml = posters_service.render_kometa_metadata()
+    return PlainTextResponse(
+        content=yaml,
+        media_type="text/yaml; charset=utf-8",
+        # YAML changes only when the Jolpica schedule changes — cache 1h.
+        headers={"Cache-Control": "public, max-age=3600"},
+    )
+
 @app.get("/circuits")
 async def get_countries():
     """Get list of all available countries with their slugs"""