Add HTTP API server, Android app, and CI build/publish pipeline

- docker-compose.yml + tooling-container/src/server.py: serve
  preprocess/OCR/extract over an async job API (POST /jobs, GET
  /jobs/{id}) instead of manual host-script runs per receipt
- android/: Kotlin/Compose app - capture a receipt photo, poll job
  progress, review/edit extracted fields, save locally (Room), export
  to CSV/ODS
- .gitea/workflows/build.yml: build the debug APK and publish it to
  dl.ladkau.de on push
- build-image.sh: also pull ollama/ollama so all pipeline images are
  ready after one script
- add project logo (also used for the app's launcher icon/splash)

tooling-container/Dockerfile

@@ -11,7 +11,10 @@ RUN pip install --no-cache-dir \
         pillow==11.0.0 \
         pytesseract==0.3.13 \
         requests==2.32.3 \
-        odfpy==1.4.1
+        odfpy==1.4.1 \
+        fastapi==0.115.5 \
+        uvicorn[standard]==0.32.1 \
+        python-multipart==0.0.17
 
 COPY src/ /opt/app/src/
 RUN chmod -R a+rX /opt/app/src