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.

build-image.sh

@@ -0,0 +1,34 @@
+#!/usr/bin/env bash
+# Builds the gastronomy tools image (tooling-container/Dockerfile) locally, tagged with
+# tooling-container/VERSION and :latest. Does not push - test it with the numbered
+# pipeline scripts first, then publish with ./upload-image.sh.
+set -euo pipefail
+
+cd "$(dirname "${BASH_SOURCE[0]}")"
+ROOT="$(pwd)"
+
+fail() { echo "PREFLIGHT FAIL: $*" >&2; exit 1; }
+
+command -v docker >/dev/null 2>&1 \
+    || fail "docker not found in PATH"
+
+IMAGE="${REGISTRY_IMAGE:-gastronomy/tools}"
+if [ -f "$ROOT/registry.env" ]; then
+    # shellcheck disable=SC1091
+    source "$ROOT/registry.env"
+    IMAGE="${REGISTRY_IMAGE:-$IMAGE}"
+fi
+
+VERSION="$(<"$ROOT/tooling-container/VERSION")"
+[ -n "$VERSION" ] || fail "tooling-container/VERSION is empty"
+
+echo "== Building $IMAGE:$VERSION =="
+docker build \
+    -f "$ROOT/tooling-container/Dockerfile" \
+    -t "$IMAGE:$VERSION" \
+    -t "$IMAGE:latest" \
+    "$ROOT/tooling-container"
+
+echo "== Done =="
+echo "Image: $IMAGE:$VERSION (and :latest)"
+echo "Test it with the numbered pipeline scripts, then publish with ./upload-image.sh"