fix(ci): use match pattern for Docker tags to support 2-part versions

The semver pattern in docker/metadata-action requires 3-part versions
(e.g. v0.29.0). Our tags use 2-part (v0.29), causing the metadata
step to produce empty tags, which made build-push-action fail.

Fix: use type=match with regex to extract the version string directly,
plus type=raw for the latest tag unconditionally.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.github/workflows/release.yml

@@ -40,9 +40,8 @@ jobs:
         with:
           images: ghcr.io/${{ github.repository }}
           tags: |
-            type=semver,pattern={{version}}
+            type=match,pattern=v(.*),group=1
-            type=semver,pattern={{major}}.{{minor}}
+            type=raw,value=latest
-            type=raw,value=latest,enable={{is_default_branch}}
 
       # Build and push multi-arch image (amd64 + arm64)
       - name: Build and push Docker image