feat(spotify): wire setup wizard into 'hermes tools' + document cron usage (#15180)

A — 'hermes tools' activation now runs the full Spotify wizard.

Previously a user had to (1) toggle the Spotify toolset on in 'hermes
tools' AND (2) separately run 'hermes auth spotify' to actually use
it. The second step was a discovery gap — the docs mentioned it but
nothing in the TUI pointed users there.

Now toggling Spotify on calls login_spotify_command as a post_setup
hook. If the user has no client_id yet, the interactive wizard walks
them through Spotify app creation; if they do, it skips straight to
PKCE. Either way, one 'hermes tools' pass leaves Spotify toggled on
AND authenticated. SystemExit from the wizard (user abort) leaves the
toolset enabled and prints a 'run: hermes auth spotify' hint — it
does NOT fail the toolset toggle.

Dropped the TOOL_CATEGORIES env_vars list for Spotify. The wizard
handles HERMES_SPOTIFY_CLIENT_ID persistence itself, and asking users
to type env var names before the wizard fires was UX-backwards — the
point of the wizard is that they don't HAVE a client_id yet.

B — Docs page now covers cron + Spotify.

New 'Scheduling: Spotify + cron' section with two working examples
(morning playlist, wind-down pause) using the real 'hermes cron add'
CLI surface (verified via 'cron add --help'). Covers the active-device
gotcha, Premium gating, memory isolation, and links to the cron docs.

Also fixed a stale '9 Spotify tools' reference in the setup copy —
we consolidated to 7 tools in #15154.

Validation:
- scripts/run_tests.sh tests/hermes_cli/test_tools_config.py
    tests/hermes_cli/test_spotify_auth.py
    tests/tools/test_spotify_client.py
  → 54 passed
- website: node scripts/prebuild.mjs && npx docusaurus build
  → SUCCESS, no new warnings

hermes_cli/tools_config.py

@@ -368,13 +368,9 @@ TOOL_CATEGORIES = {
         "providers": [
             {
                 "name": "Spotify Web API",
-                "tag": "PKCE OAuth — run `hermes auth spotify` after this",
-                "env_vars": [
-                    {"key": "HERMES_SPOTIFY_CLIENT_ID", "prompt": "Spotify app client_id",
-                     "url": "https://developer.spotify.com/dashboard"},
-                    {"key": "HERMES_SPOTIFY_REDIRECT_URI", "prompt": "Redirect URI (must be allow-listed in your Spotify app)",
-                     "default": "http://127.0.0.1:43827/spotify/callback"},
-                ],
+                "tag": "PKCE OAuth — opens the setup wizard",
+                "env_vars": [],
+                "post_setup": "spotify",
             },
         ],
     },
@@ -478,6 +474,35 @@ def _run_post_setup(post_setup_key: str):
             _print_warning("    kittentts install timed out (>5min)")
             _print_info(f"    Run manually: python -m pip install -U '{wheel_url}' soundfile")
 
+    elif post_setup_key == "spotify":
+        # Run the full `hermes auth spotify` flow — if the user has no
+        # client_id yet, this drops them into the interactive wizard
+        # (opens the Spotify dashboard, prompts for client_id, persists
+        # to ~/.hermes/.env), then continues straight into PKCE. If they
+        # already have an app, it skips the wizard and just does OAuth.
+        from types import SimpleNamespace
+        try:
+            from hermes_cli.auth import login_spotify_command
+        except Exception as exc:
+            _print_warning(f"    Could not load Spotify auth: {exc}")
+            _print_info("    Run manually: hermes auth spotify")
+            return
+        _print_info("    Starting Spotify login...")
+        try:
+            login_spotify_command(SimpleNamespace(
+                client_id=None, redirect_uri=None, scope=None,
+                no_browser=False, timeout=None,
+            ))
+            _print_success("    Spotify authenticated")
+        except SystemExit as exc:
+            # User aborted the wizard, or OAuth failed — don't fail the
+            # toolset enable; they can retry with `hermes auth spotify`.
+            _print_warning(f"    Spotify login did not complete: {exc}")
+            _print_info("    Run later: hermes auth spotify")
+        except Exception as exc:
+            _print_warning(f"    Spotify login failed: {exc}")
+            _print_info("    Run manually: hermes auth spotify")
+
     elif post_setup_key == "rl_training":
         try:
             __import__("tinker_atropos")