fix(build): sync VERSION file with semantic-release tags and add build time

- Update generate_build_metadata.sh to sync VERSION from latest git tag
- Change BUILD_DATE format from date-only to ISO 8601 with time (YYYY-MM-DDTHH:MM:SSZ)
- Fix VERSION file from 0.5.0 to 0.9.1 (matching latest git tag v0.9.1)
- Change version fallback from hardcoded '0.5.0-dev' to 'unknown' in config.py
- Update release.yml to commit all build metadata files (not just VERSION)
- Update BuildMetadata.md documentation to reflect automated versioning
- Add tests for build_date with time format and version unknown fallback

Co-authored-by: christianlouis <361235+christianlouis@users.noreply.github.com>

.github/workflows/release.yml

@@ -49,14 +49,16 @@ jobs:
           semantic-release version
           semantic-release publish
       
-      - name: Update VERSION file if changed
+      - name: Update build metadata files if changed
         run: |
-          if [ -f VERSION ]; then
-            git add VERSION
-            if ! git diff --staged --quiet; then
-              git commit -m "chore(release): update VERSION file [skip ci]"
-              git push
+          for f in VERSION BUILD_DATE GIT_SHA RUNTIME_INFO; do
+            if [ -f "$f" ]; then
+              git add "$f"
             fi
+          done
+          if ! git diff --staged --quiet; then
+            git commit -m "chore(release): update build metadata files [skip ci]"
+            git push
           fi
       
       - name: Trigger Docker Build on Tag