feat: add versioning infrastructure and release script

- Fix version mismatch: __init__.py had 'v1.0.0', pyproject.toml had '0.1.0'
  Now both use '0.1.0' (no v prefix — added in display code only)
- Add __release_date__ for CalVer date tracking alongside SemVer version
- Fix double-v bug in cmd_version (was printing 'vv1.0.0')
- Update banner title to show 'Hermes Agent v0.1.0 (2026.3.12)' format
- Update cli.py banner to match new format
- Add scripts/release.py: full release automation tool
  - Generates categorized changelogs from git history
  - Maps git authors to GitHub @mentions (70+ contributors)
  - Supports dry-run preview and --publish mode
  - Creates annotated CalVer git tags + GitHub Releases
  - Bumps semver in source files automatically
  - Usage: python scripts/release.py --bump minor --publish
- Add .release_notes.md to .gitignore

Versioning scheme: CalVer tags (v2026.3.12) + SemVer display (v0.1.0)

hermes_cli/main.py

@@ -51,7 +51,7 @@ os.environ.setdefault("MSWEA_SILENT_STARTUP", "1")
 
 import logging
 
-from hermes_cli import __version__
+from hermes_cli import __version__, __release_date__
 from hermes_constants import OPENROUTER_BASE_URL
 
 logger = logging.getLogger(__name__)
@@ -1484,7 +1484,7 @@ def cmd_config(args):
 
 def cmd_version(args):
     """Show version."""
-    print(f"Hermes Agent v{__version__}")
+    print(f"Hermes Agent v{__version__} ({__release_date__})")
     print(f"Project: {PROJECT_ROOT}")
     
     # Show Python version