f1-circuits: become a nox mesh module

The mesh builds the CDN from this repository and a commit (novox/hq ADR
0069); registry-api.novox.be, where HAL's image came from, is retired, so
the running container can no longer be re-pulled. The HAL module.yml and
service/docker-compose.yml retire with HAL.

The Kometa metadata links every poster to this service's own address,
which was the literal https://f1-circuits.zurag.be. It is now
F1_CIRCUITS_BASE_URL, written by the mesh from the route's name
(${bound:route:name}, mesh-controller #149) - falling back to the old
address, so HAL's deployment behaves as before. The tile user agent
follows it.

The poster cache is a placed directory mounted at /app/cache, as HAL's
/services/f1-circuits/cache was. The image was built from unpinned pip
installs; service/requirements.txt now pins the exact set the running
container has (pip freeze), and the base is python 3.12.13-alpine3.24 by
digest (a later alpine 3.24 patch than the running build's 3.24.0 - the
older digest is no longer tagged). The slug "f1" keeps the route login
within 20 characters on any machine.

Verified: the manifest parses on mesh-controller main and #149 and
renders for a zurag.be node (F1_CIRCUITS_BASE_URL=https://f1-circuits.
zurag.be). Built from this commit and run on an empty cache: /circuits,
/circuits/<country> and a rendered Spa track are byte-identical to what
ace serves today; the base URL comes from the variable, and without it
falls back to the old address.

Depends on mesh-controller #149.

service/Dockerfile

@@ -1,4 +1,8 @@
-FROM python:3.12-alpine
+# The base arrives pinned from module.json's build.on (python 3.12.13 on alpine 3.24); the mesh
+# builds this image from this repository and a commit (novox/hq ADR 0069). The build context is
+# the repository root, so every COPY names its path from there.
+ARG PYTHON_BASE
+FROM ${PYTHON_BASE}
 
 WORKDIR /app
 
@@ -14,13 +18,9 @@ RUN apk add --no-cache \
 
 # All pip deps ship musllinux wheels — no build-deps needed.
 # numpy is pulled in by models/geo_json/geometry.py for vector ops at import time.
-RUN pip install --no-cache-dir \
-        fastapi \
-        uvicorn \
-        python-slugify \
-        pillow \
-        cairosvg \
-        numpy
+# The versions are the ones the running deployment had (service/requirements.txt).
+COPY service/requirements.txt ./requirements.txt
+RUN pip install --no-cache-dir -r requirements.txt
 
 COPY cdn-api.py circuits_service.py ergast_service.py posters_service.py ./
 COPY models/ ./models/