Split the monolithic build-image.sh into three scripts: build-image.sh now only builds locally, run-image.sh

runs dist.sh inside that local image via a bind mount, andcupload-image.sh pushes the already-built image.
The Dockerfile also warms the Gradle dependency cache in a throwaway build stage, and pre-installs
the pinned CMake version, so `run-image.sh` doesn't re-download the same Maven dependencies on every run.

dist.sh now strips the -pre+meta suffix before writing package.json's version, since Pebble's build
tooling parses it strictly as X.Y.Z integers and was rejecting suffixed versions.

build-image.sh

@@ -1,8 +1,7 @@
 #!/usr/bin/env bash
-# Builds and pushes the release build environment image (build-image/Dockerfile)
-# to the container registry. The Gitea Actions release workflow pulls this
-# image to run dist.sh. Bump build-image/VERSION whenever the Dockerfile
-# changes so the workflow can pin a stable tag.
+# Builds the release build environment image (build-image/Dockerfile)
+# locally, tagged with build-image/VERSION and :latest. Does not push —
+# test it with ./run-image.sh first, then publish with ./upload-image.sh.
 set -euo pipefail
 
 cd "$(dirname "${BASH_SOURCE[0]}")"
@@ -19,27 +18,21 @@ command -v docker >/dev/null 2>&1 \
 # shellcheck disable=SC1091
 source "$ROOT/registry.env"
 
-: "${REGISTRY:?registry.env must set REGISTRY}"
 : "${REGISTRY_IMAGE:?registry.env must set REGISTRY_IMAGE}"
-: "${REGISTRY_USER:?registry.env must set REGISTRY_USER}"
-: "${REGISTRY_PASSWORD:?registry.env must set REGISTRY_PASSWORD}"
 
 VERSION="$(<"$ROOT/build-image/VERSION")"
 [ -n "$VERSION" ] || fail "build-image/VERSION is empty"
 
-echo "== Logging in to $REGISTRY =="
-echo "$REGISTRY_PASSWORD" | docker login "$REGISTRY" -u "$REGISTRY_USER" --password-stdin
-
 echo "== Building $REGISTRY_IMAGE:$VERSION =="
+# Context is the repo root (not build-image/) so the Dockerfile's
+# gradle-cache-warm stage can COPY in the companion app's real Gradle
+# project files — see .dockerignore for what's excluded from that context.
 docker build \
     -t "$REGISTRY_IMAGE:$VERSION" \
     -t "$REGISTRY_IMAGE:latest" \
     -f "$ROOT/build-image/Dockerfile" \
-    "$ROOT/build-image"
-
-echo "== Pushing $REGISTRY_IMAGE:$VERSION and :latest =="
-docker push "$REGISTRY_IMAGE:$VERSION"
-docker push "$REGISTRY_IMAGE:latest"
+    "$ROOT"
 
 echo "== Done =="
-echo "Image: $REGISTRY_IMAGE:$VERSION"
+echo "Image: $REGISTRY_IMAGE:$VERSION (and :latest)"
+echo "Test it with ./run-image.sh, then publish with ./upload-image.sh"