chore: bump version to v2026.4.310 and fix submodule URL handling}
- Bump version from v2026.4.309 to v2026.4.310 across all docs and badges
- Bump package.json version from 2026.4.310 to 2026.4.311
- Add v2026.4.310 changelog entry for blame view syntax highlighting
- Fix Tree.php submodule URL lookup to safely check array existence
before accessing submodule URL, preventing errors when submodule
config is missing or malformed