feat: add profiles — run multiple isolated Hermes instances (#3681)

Each profile is a fully independent HERMES_HOME with its own config,
API keys, memory, sessions, skills, gateway, cron, and state.db.

Core module: hermes_cli/profiles.py (~900 lines)
  - Profile CRUD: create, delete, list, show, rename
  - Three clone levels: blank, --clone (config), --clone-all (everything)
  - Export/import: tar.gz archive for backup and migration
  - Wrapper alias scripts (~/.local/bin/<name>)
  - Collision detection for alias names
  - Sticky default via ~/.hermes/active_profile
  - Skill seeding via subprocess (handles module-level caching)
  - Auto-stop gateway on delete with disable-before-stop for services
  - Tab completion generation for bash and zsh

CLI integration (hermes_cli/main.py):
  - _apply_profile_override(): pre-import -p/--profile flag + sticky default
  - Full 'hermes profile' subcommand: list, use, create, delete, show,
    alias, rename, export, import
  - 'hermes completion bash/zsh' command
  - Multi-profile skill sync in hermes update

Display (cli.py, banner.py, gateway/run.py):
  - CLI prompt: 'coder ❯' when using a non-default profile
  - Banner shows profile name
  - Gateway startup log includes profile name

Gateway safety:
  - Token locks: Discord, Slack, WhatsApp, Signal (extends Telegram pattern)
  - Port conflict detection: API server, webhook adapter

Diagnostics (hermes_cli/doctor.py):
  - Profile health section: lists profiles, checks config, .env, aliases
  - Orphan alias detection: warns when wrapper points to deleted profile

Tests (tests/hermes_cli/test_profiles.py):
  - 71 automated tests covering: validation, CRUD, clone levels, rename,
    export/import, active profile, isolation, alias collision, completion
  - Full suite: 6760 passed, 0 new failures

Documentation:
  - website/docs/user-guide/profiles.md: full user guide (12 sections)
  - website/docs/reference/profile-commands.md: command reference (12 commands)
  - website/docs/reference/faq.md: 6 profile FAQ entries
  - website/sidebars.ts: navigation updated

AGENTS.md

@@ -210,6 +210,10 @@ registry.register(
 
 The registry handles schema collection, dispatch, availability checking, and error wrapping. All handlers MUST return a JSON string.
 
+**Path references in tool schemas**: If the schema description mentions file paths (e.g. default output directories), use `display_hermes_home()` to make them profile-aware. The schema is generated at import time, which is after `_apply_profile_override()` sets `HERMES_HOME`.
+
+**State files**: If a tool stores persistent state (caches, logs, checkpoints), use `get_hermes_home()` for the base directory — never `Path.home() / ".hermes"`. This ensures each profile gets its own state.
+
 **Agent-level tools** (todo, memory): intercepted by `run_agent.py` before `handle_function_call()`. See `todo_tool.py` for the pattern.
 
 ---
@@ -358,8 +362,69 @@ in config.yaml (or `HERMES_BACKGROUND_NOTIFICATIONS` env var):
 
 ---
 
+## Profiles: Multi-Instance Support
+
+Hermes supports **profiles** — multiple fully isolated instances, each with its own
+`HERMES_HOME` directory (config, API keys, memory, sessions, skills, gateway, etc.).
+
+The core mechanism: `_apply_profile_override()` in `hermes_cli/main.py` sets
+`HERMES_HOME` before any module imports. All 119+ references to `get_hermes_home()`
+automatically scope to the active profile.
+
+### Rules for profile-safe code
+
+1. **Use `get_hermes_home()` for all HERMES_HOME paths.** Import from `hermes_constants`.
+   NEVER hardcode `~/.hermes` or `Path.home() / ".hermes"` in code that reads/writes state.
+   ```python
+   # GOOD
+   from hermes_constants import get_hermes_home
+   config_path = get_hermes_home() / "config.yaml"
+
+   # BAD — breaks profiles
+   config_path = Path.home() / ".hermes" / "config.yaml"
+   ```
+
+2. **Use `display_hermes_home()` for user-facing messages.** Import from `hermes_constants`.
+   This returns `~/.hermes` for default or `~/.hermes/profiles/<name>` for profiles.
+   ```python
+   # GOOD
+   from hermes_constants import display_hermes_home
+   print(f"Config saved to {display_hermes_home()}/config.yaml")
+
+   # BAD — shows wrong path for profiles
+   print("Config saved to ~/.hermes/config.yaml")
+   ```
+
+3. **Module-level constants are fine** — they cache `get_hermes_home()` at import time,
+   which is AFTER `_apply_profile_override()` sets the env var. Just use `get_hermes_home()`,
+   not `Path.home() / ".hermes"`.
+
+4. **Tests that mock `Path.home()` must also set `HERMES_HOME`** — since code now uses
+   `get_hermes_home()` (reads env var), not `Path.home() / ".hermes"`:
+   ```python
+   with patch.object(Path, "home", return_value=tmp_path), \
+        patch.dict(os.environ, {"HERMES_HOME": str(tmp_path / ".hermes")}):
+       ...
+   ```
+
+5. **Gateway platform adapters should use token locks** — if the adapter connects with
+   a unique credential (bot token, API key), call `acquire_scoped_lock()` from
+   `gateway.status` in the `connect()`/`start()` method and `release_scoped_lock()` in
+   `disconnect()`/`stop()`. This prevents two profiles from using the same credential.
+   See `gateway/platforms/telegram.py` for the canonical pattern.
+
+6. **Profile operations are HOME-anchored, not HERMES_HOME-anchored** — `_get_profiles_root()`
+   returns `Path.home() / ".hermes" / "profiles"`, NOT `get_hermes_home() / "profiles"`.
+   This is intentional — it lets `hermes -p coder profile list` see all profiles regardless
+   of which one is active.
+
 ## Known Pitfalls
 
+### DO NOT hardcode `~/.hermes` paths
+Use `get_hermes_home()` from `hermes_constants` for code paths. Use `display_hermes_home()`
+for user-facing print/log messages. Hardcoding `~/.hermes` breaks profiles — each profile
+has its own `HERMES_HOME` directory. This was the source of 5 bugs fixed in PR #3575.
+
 ### DO NOT use `simple_term_menu` for interactive menus
 Rendering bugs in tmux/iTerm2 — ghosting on scroll. Use `curses` (stdlib) instead. See `hermes_cli/tools_config.py` for the pattern.
 
@@ -375,6 +440,19 @@ Tool schema descriptions must not mention tools from other toolsets by name (e.g
 ### Tests must not write to `~/.hermes/`
 The `_isolate_hermes_home` autouse fixture in `tests/conftest.py` redirects `HERMES_HOME` to a temp dir. Never hardcode `~/.hermes/` paths in tests.
 
+**Profile tests**: When testing profile features, also mock `Path.home()` so that
+`_get_profiles_root()` and `_get_default_hermes_home()` resolve within the temp dir.
+Use the pattern from `tests/hermes_cli/test_profiles.py`:
+```python
+@pytest.fixture
+def profile_env(tmp_path, monkeypatch):
+    home = tmp_path / ".hermes"
+    home.mkdir()
+    monkeypatch.setattr(Path, "home", lambda: tmp_path)
+    monkeypatch.setenv("HERMES_HOME", str(home))
+    return home
+```
+
 ---
 
 ## Testing