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.

run_agent.py

@@ -45,7 +45,7 @@ import fire
 from datetime import datetime
 from pathlib import Path
 
-from hermes_constants import get_hermes_home, display_hermes_home
+from hermes_constants import get_hermes_home
 
 # Load .env from ~/.hermes/.env first, then project root as dev fallback.
 # User-managed env files should override stale shell exports on restart.
@@ -6924,7 +6924,8 @@ class AIAgent:
                         print(f"{self.log_prefix}   Auth method: {auth_method}")
                         print(f"{self.log_prefix}   Token prefix: {key[:12]}..." if key and len(key) > 12 else f"{self.log_prefix}   Token: (empty or short)")
                         print(f"{self.log_prefix}   Troubleshooting:")
-                        _dhh = display_hermes_home()
+                        from hermes_constants import display_hermes_home as _dhh_fn
+                        _dhh = _dhh_fn()
                         print(f"{self.log_prefix}     • Check ANTHROPIC_TOKEN in {_dhh}/.env for Hermes-managed OAuth/setup tokens")
                         print(f"{self.log_prefix}     • Check ANTHROPIC_API_KEY in {_dhh}/.env for API keys or legacy token values")
                         print(f"{self.log_prefix}     • For API keys: verify at https://console.anthropic.com/settings/keys")