refactor: codebase-wide lint cleanup — unused imports, dead code, and inefficient patterns (#5821)

Comprehensive cleanup across 80 files based on automated (ruff, pyflakes, vulture)
and manual analysis of the entire codebase.

Changes by category:

Unused imports removed (~95 across 55 files):
- Removed genuinely unused imports from all major subsystems
- agent/, hermes_cli/, tools/, gateway/, plugins/, cron/
- Includes imports in try/except blocks that were truly unused
  (vs availability checks which were left alone)

Unused variables removed (~25):
- Removed dead variables: connected, inner, channels, last_exc,
  source, new_server_names, verify, pconfig, default_terminal,
  result, pending_handled, temperature, loop
- Dropped unused argparse subparser assignments in hermes_cli/main.py
  (12 instances of add_parser() where result was never used)

Dead code removed:
- run_agent.py: Removed dead ternary (None if False else None) and
  surrounding unreachable branch in identity fallback
- run_agent.py: Removed write-only attribute _last_reported_tool
- hermes_cli/providers.py: Removed dead @property decorator on
  module-level function (decorator has no effect outside a class)
- gateway/run.py: Removed unused MCP config load before reconnect
- gateway/platforms/slack.py: Removed dead SessionSource construction

Undefined name bugs fixed (would cause NameError at runtime):
- batch_runner.py: Added missing logger = logging.getLogger(__name__)
- tools/environments/daytona.py: Added missing Dict and Path imports

Unnecessary global statements removed (14):
- tools/terminal_tool.py: 5 functions declared global for dicts
  they only mutated via .pop()/[key]=value (no rebinding)
- tools/browser_tool.py: cleanup thread loop only reads flag
- tools/rl_training_tool.py: 4 functions only do dict mutations
- tools/mcp_oauth.py: only reads the global
- hermes_time.py: only reads cached values

Inefficient patterns fixed:
- startswith/endswith tuple form: 15 instances of
  x.startswith('a') or x.startswith('b') consolidated to
  x.startswith(('a', 'b'))
- len(x)==0 / len(x)>0: 13 instances replaced with pythonic
  truthiness checks (not x / bool(x))
- in dict.keys(): 5 instances simplified to in dict
- Redefined unused name: removed duplicate _strip_mdv2 import in
  send_message_tool.py

Other fixes:
- hermes_cli/doctor.py: Replaced undefined logger.debug() with pass
- hermes_cli/config.py: Consolidated chained .endswith() calls

Test results: 3934 passed, 17 failed (all pre-existing on main),
19 skipped. Zero regressions.

plugins/memory/byterover/__init__.py

@@ -23,7 +23,6 @@ import os
 import shutil
 import subprocess
 import threading
-import time
 from pathlib import Path
 from typing import Any, Dict, List, Optional
 

plugins/memory/holographic/__init__.py

@@ -20,7 +20,6 @@ from __future__ import annotations
 import json
 import logging
 import re
-from pathlib import Path
 from typing import Any, Dict, List
 
 from agent.memory_provider import MemoryProvider

plugins/memory/holographic/store.py

@@ -6,7 +6,6 @@ Single-user Hermes memory store plugin.
 import re
 import sqlite3
 import threading
-from datetime import datetime
 from pathlib import Path
 
 try:

plugins/memory/honcho/__init__.py

@@ -18,7 +18,6 @@ from __future__ import annotations
 import json
 import logging
 import threading
-from pathlib import Path
 from typing import Any, Dict, List, Optional
 
 from agent.memory_provider import MemoryProvider

plugins/memory/honcho/cli.py

@@ -11,7 +11,7 @@ import sys
 from pathlib import Path
 
 from hermes_constants import get_hermes_home
-from plugins.memory.honcho.client import resolve_active_host, resolve_config_path, GLOBAL_CONFIG_PATH, HOST
+from plugins.memory.honcho.client import resolve_active_host, resolve_config_path, HOST
 
 
 def clone_honcho_for_profile(profile_name: str) -> bool:
@@ -1220,7 +1220,6 @@ def register_cli(subparser) -> None:
     Called by the plugin CLI registration system during argparse setup.
     The *subparser* is the parser for ``hermes honcho``.
     """
-    import argparse
 
     subparser.add_argument(
         "--target-profile", metavar="NAME", dest="target_profile",

plugins/memory/mem0/__init__.py

@@ -20,7 +20,6 @@ import logging
 import os
 import threading
 import time
-from pathlib import Path
 from typing import Any, Dict, List
 
 from agent.memory_provider import MemoryProvider

plugins/memory/retaindb/__init__.py

@@ -20,7 +20,6 @@ Config (env vars or hermes config.yaml under retaindb:):
 
 from __future__ import annotations
 
-import hashlib
 import json
 import logging
 import os
@@ -189,7 +188,7 @@ class _Client:
             "Content-Type": "application/json",
             "x-sdk-runtime": "hermes-plugin",
         }
-        if path.startswith("/v1/memory") or path.startswith("/v1/context"):
+        if path.startswith(("/v1/memory", "/v1/context")):
             h["X-API-Key"] = token
         return h