chore: adopt vYYYY.MM.DD.HHMMSS.COMMIT versioning scheme

Change from v0.1.YYYYMMDD.HHMMSS.COMMIT to vYYYY.MM.DD.HHMMSS.COMMIT
to align with BizPrint versioning style:
- Semantic year.month.day separation via dots
- Preserves hourly precision (HHMMSS)
- Includes commit hash for traceability

Example: v2026.07.24.165410.7bd491e

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

.gitea/workflows/prepare-release.yml

@@ -64,9 +64,9 @@ jobs:
           if [ -z "$VERSION_INPUT" ]; then
             # Simple, reliable version scheme: timestamp + commit hash
             # Avoids unreliable Gitea API calls (network failures, timeouts)
-            # Format: v0.1.YYYYMMDD.HHMMSS.COMMIT
-            TIMESTAMP=$(TZ=Asia/Seoul date +%Y%m%d.%H%M%S)
-            VERSION="v0.1.${TIMESTAMP}.${COMMIT}"
+            # Format: vYYYY.MM.DD.HHMMSS.COMMIT
+            TIMESTAMP=$(TZ=Asia/Seoul date +%Y.%m.%d.%H%M%S)
+            VERSION="v${TIMESTAMP}.${COMMIT}"
           else
             VERSION="$VERSION_INPUT"
           fi