feat: auto-version workflow — tags managed by commit messages

Adds .github/workflows/auto-version.yml that fires on every push to
main, parses commit messages since the last semver tag, and decides
whether to cut a new release:

  feat:      → minor bump   (new feature, backward-compatible)
  fix:       → patch bump   (bug fix)
  feat!:     → major bump   (breaking change)
  BREAKING CHANGE in body → major bump
  docs/chore/refactor/style/test/ci → no release

If any commit since the last tag matches feat/fix/BREAKING, the
workflow bumps versions across package.json, mobile/package.json,
mobile/android/app/build.gradle, commits the change as
"Release vX.Y.Z", tags it, and pushes. The tag push then fires the
existing android-release and docker-publish workflows.

You no longer need to remember "what version am I on?" — just commit
with a conventional-commits prefix and push. Docs-only or refactor
commits don't create releases. Add [skip ci] to any commit message
to skip this workflow for that commit.

.github/workflows/auto-version.yml

@@ -0,0 +1,137 @@
+name: Auto version & release
+
+# Fires on every push to main. Parses commit messages since the
+# last semver tag, decides patch/minor/major bump, creates the
+# tag, pushes. The tag push then triggers android-release.yml and
+# docker-publish.yml. Fully hands-off — you never pick a version
+# number; your commit messages do.
+#
+# Commit message grammar (Conventional Commits):
+#   feat:  → minor bump   (new feature, backward-compatible)
+#   fix:   → patch bump   (bug fix)
+#   feat!: / BREAKING CHANGE in body → major bump
+#   everything else (docs, refactor, chore, style, ci, test) → no bump
+#
+# Skip conditions (no new release created):
+#   - No commits match the above patterns
+#   - The most recent commit is itself a release commit ("Release v…")
+#   - [skip ci] appears in any commit message since the last tag
+
+on:
+  push:
+    branches: [main]
+
+permissions:
+  contents: write
+
+jobs:
+  version:
+    runs-on: ubuntu-latest
+    if: "!contains(github.event.head_commit.message, 'Release v') && !contains(github.event.head_commit.message, '[skip ci]')"
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+          token: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Find last semver tag
+        id: last
+        run: |
+          LAST=$(git tag --list 'v[0-9]*.[0-9]*.[0-9]*' --sort=-v:refname | head -1)
+          if [[ -z "$LAST" ]]; then
+            LAST="v0.0.0"
+            echo "no previous tag, starting from v0.0.0"
+          fi
+          echo "tag=$LAST"
+          echo "tag=$LAST" >> "$GITHUB_OUTPUT"
+          echo "version=${LAST#v}" >> "$GITHUB_OUTPUT"
+
+      - name: Decide bump type from commit messages
+        id: decide
+        env:
+          LAST: ${{ steps.last.outputs.tag }}
+        run: |
+          # All commits from the last tag → HEAD (exclusive of tag commit)
+          if [[ "$LAST" == "v0.0.0" ]]; then
+            MSGS=$(git log --format='%s%n%b%n---')
+          else
+            MSGS=$(git log "${LAST}..HEAD" --format='%s%n%b%n---')
+          fi
+
+          BUMP=none
+          if echo "$MSGS" | grep -qE '(^|\n)(BREAKING CHANGE:|[a-z]+(\([^)]+\))?!:)'; then
+            BUMP=major
+          elif echo "$MSGS" | grep -qE '(^|\n)feat(\([^)]+\))?: '; then
+            BUMP=minor
+          elif echo "$MSGS" | grep -qE '(^|\n)fix(\([^)]+\))?: '; then
+            BUMP=patch
+          fi
+
+          echo "Bump type decided: $BUMP"
+          echo "bump=$BUMP" >> "$GITHUB_OUTPUT"
+          {
+            echo "### Commits since $LAST"
+            echo '```'
+            if [[ "$LAST" == "v0.0.0" ]]; then
+              git log --oneline | head -20
+            else
+              git log "${LAST}..HEAD" --oneline
+            fi
+            echo '```'
+            echo ""
+            echo "**Bump decision**: \`$BUMP\`"
+          } >> "$GITHUB_STEP_SUMMARY"
+
+      - name: Stop if no release-worthy commits
+        if: steps.decide.outputs.bump == 'none'
+        run: |
+          echo "No feat / fix / BREAKING commits since last tag — not cutting a release."
+          echo "::notice::No release cut. Commit with 'feat:', 'fix:', or BREAKING CHANGE to trigger one."
+
+      - name: Compute next version
+        id: next
+        if: steps.decide.outputs.bump != 'none'
+        env:
+          CUR: ${{ steps.last.outputs.version }}
+          BUMP: ${{ steps.decide.outputs.bump }}
+        run: |
+          IFS='.' read -r MAJ MIN PAT <<< "$CUR"
+          case "$BUMP" in
+            major) NEXT="$((MAJ+1)).0.0" ;;
+            minor) NEXT="${MAJ}.$((MIN+1)).0" ;;
+            patch) NEXT="${MAJ}.${MIN}.$((PAT+1))" ;;
+          esac
+          echo "next=$NEXT" >> "$GITHUB_OUTPUT"
+          echo "### Next version: v$NEXT" >> "$GITHUB_STEP_SUMMARY"
+
+      - name: Configure git
+        if: steps.decide.outputs.bump != 'none'
+        run: |
+          git config user.name  "github-actions[bot]"
+          git config user.email "41898282+github-actions[bot]@users.noreply.github.com"
+
+      - name: Bump version strings + tag + push
+        if: steps.decide.outputs.bump != 'none'
+        env:
+          V: ${{ steps.next.outputs.next }}
+        run: |
+          IFS='.' read -r MAJ MIN PAT <<< "$V"
+          ANDROID_CODE=$(( MAJ * 100000 + MIN * 1000 + PAT ))
+
+          sed -i -E "0,/(\"version\"[[:space:]]*:[[:space:]]*\")[^\"]+(\")/ s//\1${V}\2/" package.json
+          sed -i -E "0,/(\"version\"[[:space:]]*:[[:space:]]*\")[^\"]+(\")/ s//\1${V}\2/" mobile/package.json
+          sed -i -E \
+            -e "s/versionCode +[0-9]+/versionCode ${ANDROID_CODE}/" \
+            -e "s/versionName +\"[^\"]+\"/versionName \"${V}\"/" \
+            mobile/android/app/build.gradle
+
+          git add package.json mobile/package.json mobile/android/app/build.gradle
+          git commit -m "Release v${V}"
+          git tag -a "v${V}" -m "Release v${V}"
+
+          git push origin HEAD
+          git push origin "v${V}"
+
+          echo "### Released v$V" >> "$GITHUB_STEP_SUMMARY"
+          echo "android-release + docker-publish workflows will now run." >> "$GITHUB_STEP_SUMMARY"