refactor: remove smart_model_routing feature (#12732)

Smart model routing (auto-routing short/simple turns to a cheap model
across providers) was opt-in and disabled by default.  This removes the
feature wholesale: the routing module, its config keys, docs, tests, and
the orchestration scaffolding it required in cli.py / gateway/run.py /
cron/scheduler.py.

The /fast (Priority Processing / Anthropic fast mode) feature kept its
hooks into _resolve_turn_agent_config — those still build a route dict
and attach request_overrides when the model supports it; the route now
just always uses the session's primary model/provider rather than
running prompts through choose_cheap_model_route() first.

Also removed:
- DEFAULT_CONFIG['smart_model_routing'] block and matching commented-out
  example sections in hermes_cli/config.py and cli-config.yaml.example
- _load_smart_model_routing() / self._smart_model_routing on GatewayRunner
- self._smart_model_routing / self._active_agent_route_signature on
  HermesCLI (signature kept; just no longer initialised through the
  smart-routing pipeline)
- route_label parameter on HermesCLI._init_agent (only set by smart
  routing; never read elsewhere)
- 'Smart Model Routing' section in website/docs/integrations/providers.md
- tip in hermes_cli/tips.py
- entries in hermes_cli/dump.py + hermes_cli/web_server.py
- row in skills/autonomous-ai-agents/hermes-agent/SKILL.md

Tests:
- Deleted tests/agent/test_smart_model_routing.py
- Rewrote tests/agent/test_credential_pool_routing.py to target the
  simplified _resolve_turn_agent_config directly (preserves credential
  pool propagation + 429 rotation coverage)
- Dropped 'cheap model' test from test_cli_provider_resolution.py
- Dropped resolve_turn_route patches from cli + gateway test_fast_command
  — they now exercise the real method end-to-end
- Removed _smart_model_routing stub assignments from gateway/cron test
  helpers

Targeted suites: 74/74 in the directly affected test files;
tests/agent + tests/cron + tests/cli pass except 5 failures that
already exist on main (cron silent-delivery + alias quick-command).

website/docs/integrations/providers.md

@@ -1165,39 +1165,6 @@ Supported providers: `openrouter`, `nous`, `openai-codex`, `copilot`, `copilot-a
 Fallback is configured exclusively through `config.yaml` — there are no environment variables for it. For full details on when it triggers, supported providers, and how it interacts with auxiliary tasks and delegation, see [Fallback Providers](/docs/user-guide/features/fallback-providers).
 :::
 
-## Smart Model Routing
-
-Optional cheap-vs-strong routing lets Hermes keep your main model for complex work while sending very short/simple turns to a cheaper model.
-
-```yaml
-smart_model_routing:
-  enabled: true
-  max_simple_chars: 160
-  max_simple_words: 28
-  cheap_model:
-    provider: openrouter
-    model: google/gemini-2.5-flash
-    # base_url: http://localhost:8000/v1  # optional custom endpoint
-    # key_env: MY_CUSTOM_KEY              # optional env var name for that endpoint's API key
-```
-
-How it works:
-- If a turn is short, single-line, and does not look code/tool/debug heavy, Hermes may route it to `cheap_model`
-- If the turn looks complex, Hermes stays on your primary model/provider
-- If the cheap route cannot be resolved cleanly, Hermes falls back to the primary model automatically
-
-This is intentionally conservative. It is meant for quick, low-stakes turns like:
-- short factual questions
-- quick rewrites
-- lightweight summaries
-
-It will avoid routing prompts that look like:
-- coding/debugging work
-- tool-heavy requests
-- long or multi-line analysis asks
-
-Use this when you want lower latency or cost without fully changing your default model.
-
 ---
 
 ## See Also