Include git SHA in /version output via banner label helper.

Reuses format_banner_version_label() so CLI, TUI, gateway, and desktop show upstream/local commit when available.

tests/gateway/test_version_command.py

@@ -2,11 +2,11 @@
 
 import asyncio
 
-from hermes_cli import __release_date__, __version__
+from hermes_cli.banner import format_banner_version_label
 
 
 def test_gateway_version_command_returns_release_line():
     from gateway.run import GatewayRunner
 
     result = asyncio.run(GatewayRunner._handle_version_command(None, None))  # type: ignore[arg-type]
-    assert result == f"Hermes Agent v{__version__} ({__release_date__})"
+    assert result == format_banner_version_label()