refactor: extract shared helpers to deduplicate repeated code patterns (#7917)

* refactor: add shared helper modules for code deduplication

New modules:
- gateway/platforms/helpers.py: MessageDeduplicator, TextBatchAggregator,
  strip_markdown, ThreadParticipationTracker, redact_phone
- hermes_cli/cli_output.py: print_info/success/warning/error, prompt helpers
- tools/path_security.py: validate_within_dir, has_traversal_component
- utils.py additions: safe_json_loads, read_json_file, read_jsonl,
  append_jsonl, env_str/lower/int/bool helpers
- hermes_constants.py additions: get_config_path, get_skills_dir,
  get_logs_dir, get_env_path

* refactor: migrate gateway adapters to shared helpers

- MessageDeduplicator: discord, slack, dingtalk, wecom, weixin, mattermost
- strip_markdown: bluebubbles, feishu, sms
- redact_phone: sms, signal
- ThreadParticipationTracker: discord, matrix
- _acquire/_release_platform_lock: telegram, discord, slack, whatsapp,
  signal, weixin

Net -316 lines across 19 files.

* refactor: migrate CLI modules to shared helpers

- tools_config.py: use cli_output print/prompt + curses_radiolist (-117 lines)
- setup.py: use cli_output print helpers + curses_radiolist (-101 lines)
- mcp_config.py: use cli_output prompt (-15 lines)
- memory_setup.py: use curses_radiolist (-86 lines)

Net -263 lines across 5 files.

* refactor: migrate to shared utility helpers

- safe_json_loads: agent/display.py (4 sites)
- get_config_path: skill_utils.py, hermes_logging.py, hermes_time.py
- get_skills_dir: skill_utils.py, prompt_builder.py
- Token estimation dedup: skills_tool.py imports from model_metadata
- Path security: skills_tool, cronjob_tools, skill_manager_tool, credential_files
- Non-atomic YAML writes: doctor.py, config.py now use atomic_yaml_write
- Platform dict: new platforms.py, skills_config + tools_config derive from it
- Anthropic key: new get_anthropic_key() in auth.py, used by doctor/status/config/main

* test: update tests for shared helper migrations

- test_dingtalk: use _dedup.is_duplicate() instead of _is_duplicate()
- test_mattermost: use _dedup instead of _seen_posts/_prune_seen
- test_signal: import redact_phone from helpers instead of signal
- test_discord_connect: _platform_lock_identity instead of _token_lock_identity
- test_telegram_conflict: updated lock error message format
- test_skill_manager_tool: 'escapes' instead of 'boundary' in error msgs

hermes_constants.py

@@ -189,6 +189,33 @@ def is_wsl() -> bool:
     return _wsl_detected
 
 
+# ─── Well-Known Paths ─────────────────────────────────────────────────────────
+
+
+def get_config_path() -> Path:
+    """Return the path to ``config.yaml`` under HERMES_HOME.
+
+    Replaces the ``get_hermes_home() / "config.yaml"`` pattern repeated
+    in 7+ files (skill_utils.py, hermes_logging.py, hermes_time.py, etc.).
+    """
+    return get_hermes_home() / "config.yaml"
+
+
+def get_skills_dir() -> Path:
+    """Return the path to the skills directory under HERMES_HOME."""
+    return get_hermes_home() / "skills"
+
+
+def get_logs_dir() -> Path:
+    """Return the path to the logs directory under HERMES_HOME."""
+    return get_hermes_home() / "logs"
+
+
+def get_env_path() -> Path:
+    """Return the path to the ``.env`` file under HERMES_HOME."""
+    return get_hermes_home() / ".env"
+
+
 OPENROUTER_BASE_URL = "https://openrouter.ai/api/v1"
 OPENROUTER_MODELS_URL = f"{OPENROUTER_BASE_URL}/models"