fix: make display_hermes_home imports lazy to prevent ImportError during hermes update (#3776)

When a user runs 'hermes update', the Python process caches old modules
in sys.modules.  After git pull updates files on disk, lazy imports of
newly-updated modules fail because they try to import display_hermes_home
from the cached (old) hermes_constants which doesn't have the function.

This specifically broke the gateway auto-restart in cmd_update — importing
hermes_cli/gateway.py triggered the top-level 'from hermes_constants
import display_hermes_home' against the cached old module.  The ImportError
was silently caught, so the gateway was never restarted after update.

Users with a running gateway then hit the ImportError on their next
Telegram/Discord message when the stale gateway process lazily loaded
run_agent.py (new version) which also had the top-level import.

Fixes:
- hermes_cli/gateway.py: lazy import at call site (line 940)
- run_agent.py: lazy import at call site (line 6927)
- tools/terminal_tool.py: lazy imports at 3 call sites
- tools/tts_tool.py: static schema string (no module-level call)
- hermes_cli/auth.py: lazy import at call site (line 2024)
- hermes_cli/main.py: reload hermes_constants after git pull in cmd_update

Also fixes 4 pre-existing test failures in test_parse_env_var caused by
NameError on display_hermes_home in terminal_tool.py.

tools/terminal_tool.py

@@ -48,7 +48,7 @@ logger = logging.getLogger(__name__)
 # long-running subprocesses immediately instead of blocking until timeout.
 # ---------------------------------------------------------------------------
 from tools.interrupt import is_interrupted, _interrupt_event  # noqa: F401 — re-exported
-from hermes_constants import display_hermes_home
+# display_hermes_home imported lazily at call site (stale-module safety during hermes update)
 
 
 # =============================================================================
@@ -158,7 +158,8 @@ def _handle_sudo_failure(output: str, env_type: str) -> str:
     
     for failure in sudo_failures:
         if failure in output:
-            return output + f"\n\n💡 Tip: To enable sudo over messaging, add SUDO_PASSWORD to {display_hermes_home()}/.env on the agent machine."
+            from hermes_constants import display_hermes_home as _dhh
+            return output + f"\n\n💡 Tip: To enable sudo over messaging, add SUDO_PASSWORD to {_dhh()}/.env on the agent machine."
     
     return output
 
@@ -444,7 +445,7 @@ def _parse_env_var(name: str, default: str, converter=int, type_label: str = "in
     except (ValueError, json.JSONDecodeError):
         raise ValueError(
             f"Invalid value for {name}: {raw!r} (expected {type_label}). "
-            f"Check {display_hermes_home()}/.env or environment variables."
+            f"Check ~/.hermes/.env or environment variables."
         )
 
 
@@ -1284,7 +1285,8 @@ if __name__ == "__main__":
     print(f"  TERMINAL_MODAL_IMAGE: {os.getenv('TERMINAL_MODAL_IMAGE', default_img)}")
     print(f"  TERMINAL_DAYTONA_IMAGE: {os.getenv('TERMINAL_DAYTONA_IMAGE', default_img)}")
     print(f"  TERMINAL_CWD: {os.getenv('TERMINAL_CWD', os.getcwd())}")
-    print(f"  TERMINAL_SANDBOX_DIR: {os.getenv('TERMINAL_SANDBOX_DIR', f'{display_hermes_home()}/sandboxes')}")
+    from hermes_constants import display_hermes_home as _dhh
+    print(f"  TERMINAL_SANDBOX_DIR: {os.getenv('TERMINAL_SANDBOX_DIR', f'{_dhh()}/sandboxes')}")
     print(f"  TERMINAL_TIMEOUT: {os.getenv('TERMINAL_TIMEOUT', '60')}")
     print(f"  TERMINAL_LIFETIME_SECONDS: {os.getenv('TERMINAL_LIFETIME_SECONDS', '300')}")