Add containerized OCR pipeline for fuel receipts

Self-hosted, verifiable pipeline for extracting structured data (station,
date/time, price per litre, litres, discount, total) from German fuel
receipt photos: grayscale + mild bilateral filter + contrast stretch,
Tesseract OCR, then LLM structuring via a small local model (Qwen 2.5,
served by Ollama). Each step is independently runnable and inspectable
through numbered scripts against a shared tooling container.

Ollama runs as its own long-lived container (0_run_ollama.sh), separate
from the stateless per-receipt pipeline steps, so the model stays loaded
in memory between runs. Includes a containerized ground-truth batch test
(test_batch.sh) that reproduces the full pipeline over the test receipts
and reports per-field accuracy.

Targets eventual deployment on a Raspberry Pi 4 k3s cluster.

registry.env.example

@@ -0,0 +1,9 @@
+# Copy to registry.env (gitignored, never commit the real values) and fill
+# in your registry credentials. Used by build-image.sh, the numbered
+# pipeline scripts, and upload-image.sh. Only REGISTRY_IMAGE is needed for
+# local builds/runs; REGISTRY/REGISTRY_USER/REGISTRY_PASSWORD are only
+# needed to push with upload-image.sh.
+REGISTRY=
+REGISTRY_IMAGE=gastronomy/tools
+REGISTRY_USER=
+REGISTRY_PASSWORD=