test(tui): fix stale mocks + xdist flakes in TUI test suite

All 61 TUI-related tests green across 3 consecutive xdist runs.

tests/tui_gateway/test_protocol.py:
- rename `get_messages` → `get_messages_as_conversation` on mock DB (method
  was renamed in the real backend, test was still stubbing the old name)
- update tool-message shape expectation: `{role, name, context}` matches
  current `_history_to_messages` output, not the legacy `{role, text}`

tests/hermes_cli/test_tui_resume_flow.py:
- `cmd_chat` grew a first-run provider-gate that bailed to "Run: hermes
  setup" before `_launch_tui` was ever reached; 3 tests stubbed
  `_resolve_last_session` + `_launch_tui` but not the gate
- factored a `main_mod` fixture that stubs `_has_any_provider_configured`,
  reused by all three tests

tests/test_tui_gateway_server.py:
- `test_config_set_personality_resets_history_and_returns_info` was flaky
  under xdist because the real `_write_config_key` touches
  `~/.hermes/config.yaml`, racing with any other worker that writes
  config. Stub it in the test.

hermes_cli/commands.py

@@ -104,6 +104,7 @@ COMMAND_REGISTRY: list[CommandDef] = [
     CommandDef("model", "Switch model for this session", "Configuration", args_hint="[model] [--provider name] [--global]"),
     CommandDef("provider", "Show available providers and current provider",
                "Configuration"),
+    CommandDef("gquota", "Show Google Gemini Code Assist quota usage", "Info"),
 
     CommandDef("personality", "Set a predefined personality", "Configuration",
                args_hint="[name]"),