refactor(cli): migrate to commander framework and simplify config loading

Replace hand-rolled CLI argument parsing with Commander for command
registration and option handling. Streamline config resolution by
removing the BrickConfig type and accepting a plain source string
with BRICK_SOURCE env var support.

- Replace manual CLI dispatch with Commander-based command tree
- Simplify resolveConfig/resolveSource to a single resolveSource function
- Remove BrickConfig interface in favor of direct source string
- Move isRemote check into index-loader as a local utility
- Update loadIndex signature to accept source string directly

.gitea/workflows/publish.yml

@@ -12,15 +12,8 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
-
-      - uses: actions/setup-node@v4
-        with:
-          node-version: 18
-
       - run: npm ci
-
       - run: npm run build
-
       - name: Publish to Gitea npm registry
         run: |
           echo "//gitea.synoth.com/api/packages/synoth/npm/:_authToken=${{ secrets.GITEA_TOKEN }}" > ~/.npmrc