Merge branch 'feat/footer-share-ci' into dev

CI keeps the 'test once per code state' plan but records commit and
git tree as image labels instead of extra :sha-/:tree- tags, so the
registry only holds dev, latest, vX.Y.Z and stable; the plan test now
asserts the expected decisions.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

.gitea/scripts/build-plan.sh

@@ -0,0 +1,91 @@
+#!/usr/bin/env bash
+# Decides per CI run: build with tests, build without tests, or only retag an existing image.
+# Tests run once per code state: the images carry the git tree and commit as labels
+# (io.mindsift.tree, org.opencontainers.image.revision), so no extra image tags are needed.
+#   dev   -> build and test, tag :dev
+#   main  -> build :latest; tests are skipped when :dev was built from the same tree
+#   v*    -> retag :latest when it was built from this commit, else build (tests skipped when
+#            :dev or :latest has the same tree); :stable only for releases without "-"
+# Inputs (environment): REF, COMMIT (default HEAD), IMAGE, PKG_VERSION (default from package.json),
+# LABEL_CMD (prints a label of a remote image: LABEL_CMD <image> <label>; for tests)
+set -euo pipefail
+
+REF="${REF:-}"
+COMMIT="${COMMIT:-HEAD}"
+IMAGE="${IMAGE:-}"
+PKG_VERSION="${PKG_VERSION:-}"
+if [ -z "${PKG_VERSION}" ] && [ -f frontend/package.json ]; then
+  PKG_VERSION="$(sed -nE 's/^  "version": "([^"]+)".*/\1/p' frontend/package.json | head -n1)"
+fi
+
+SHA="$(git rev-parse "${COMMIT}^{commit}")"
+TREE="$(git rev-parse "${COMMIT}^{tree}")"
+
+# Label of an image in the registry ("" when the image or label does not exist)
+image_label() {
+  if [ -n "${LABEL_CMD:-}" ]; then
+    ${LABEL_CMD} "$1" "$2" 2>/dev/null || true
+    return
+  fi
+  docker pull -q "$1" >/dev/null 2>&1 || return 0
+  docker inspect -f "{{ index .Config.Labels \"$2\" }}" "$1" 2>/dev/null | sed 's/^<no value>$//' || true
+}
+
+ACTION="build"
+SKIP_TESTS="0"
+APP_VERSION=""
+TAGS=""
+SOURCE_IMAGE=""
+REASON=""
+
+case "${REF}" in
+  refs/heads/dev)
+    TAGS="dev"
+    REASON="dev: build with all tests"
+    ;;
+  refs/heads/main)
+    TAGS="latest"
+    APP_VERSION="v${PKG_VERSION}"
+    if [ -n "${IMAGE}" ] && [ "$(image_label "${IMAGE}:dev" io.mindsift.tree)" = "${TREE}" ]; then
+      SKIP_TESTS="1"
+      REASON="main: same code as the tested :dev image, tests skipped"
+    else
+      REASON="main: code not tested as :dev yet, build with all tests"
+    fi
+    ;;
+  refs/tags/v*)
+    TAG_NAME="${REF#refs/tags/}"
+    TAGS="${TAG_NAME}"
+    case "${TAG_NAME}" in *-*) ;; *) TAGS="${TAG_NAME} stable" ;; esac
+    if [ -n "${IMAGE}" ] && [ "$(image_label "${IMAGE}:latest" org.opencontainers.image.revision)" = "${SHA}" ]; then
+      ACTION="retag"
+      SOURCE_IMAGE="${IMAGE}:latest"
+      SKIP_TESTS="1"
+      REASON="tag ${TAG_NAME}: :latest was built from this commit, retag without building"
+    else
+      APP_VERSION="${TAG_NAME}"
+      if [ -n "${IMAGE}" ] && { [ "$(image_label "${IMAGE}:dev" io.mindsift.tree)" = "${TREE}" ] ||
+        [ "$(image_label "${IMAGE}:latest" io.mindsift.tree)" = "${TREE}" ]; }; then
+        SKIP_TESTS="1"
+        REASON="tag ${TAG_NAME}: code already tested, build without tests"
+      else
+        REASON="tag ${TAG_NAME}: build with all tests"
+      fi
+    fi
+    ;;
+  *)
+    TAGS="$(echo "${REF#refs/heads/}" | sed 's#/#-#g' | tr '[:upper:]' '[:lower:]')"
+    REASON="branch ${REF}: build with all tests"
+    ;;
+esac
+
+{
+  echo "action=${ACTION}"
+  echo "skip_tests=${SKIP_TESTS}"
+  echo "app_version=${APP_VERSION}"
+  echo "tags=${TAGS}"
+  echo "source_image=${SOURCE_IMAGE}"
+  echo "sha=${SHA}"
+  echo "tree=${TREE}"
+  echo "reason=${REASON}"
+} | tee -a "${GITHUB_OUTPUT:-/dev/null}"