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).

tests/cli/test_fast_command.py

@@ -183,27 +183,10 @@ class TestFastModeRouting(unittest.TestCase):
             acp_command=None,
             acp_args=[],
             _credential_pool=None,
-            _smart_model_routing={},
             service_tier="priority",
         )
 
-        original_runtime = {
-            "api_key": "***",
-            "base_url": "https://openrouter.ai/api/v1",
-            "provider": "openrouter",
-            "api_mode": "chat_completions",
-            "command": None,
-            "args": [],
-            "credential_pool": None,
-        }
-
-        with patch("agent.smart_model_routing.resolve_turn_route", return_value={
-            "model": "gpt-5.4",
-            "runtime": dict(original_runtime),
-            "label": None,
-            "signature": ("gpt-5.4", "openrouter", "https://openrouter.ai/api/v1", "chat_completions", None, ()),
-        }):
-            route = cli_mod.HermesCLI._resolve_turn_agent_config(stub, "hi")
+        route = cli_mod.HermesCLI._resolve_turn_agent_config(stub, "hi")
 
         # Provider should NOT have changed
         assert route["runtime"]["provider"] == "openrouter"
@@ -222,26 +205,10 @@ class TestFastModeRouting(unittest.TestCase):
             acp_command=None,
             acp_args=[],
             _credential_pool=None,
-            _smart_model_routing={},
             service_tier="priority",
         )
 
-        primary_route = {
-            "model": "gpt-5.3-codex",
-            "runtime": {
-                "api_key": "***",
-                "base_url": "https://openrouter.ai/api/v1",
-                "provider": "openrouter",
-                "api_mode": "chat_completions",
-                "command": None,
-                "args": [],
-                "credential_pool": None,
-            },
-            "label": None,
-            "signature": ("gpt-5.3-codex", "openrouter", "https://openrouter.ai/api/v1", "chat_completions", None, ()),
-        }
-        with patch("agent.smart_model_routing.resolve_turn_route", return_value=primary_route):
-            route = cli_mod.HermesCLI._resolve_turn_agent_config(stub, "hi")
+        route = cli_mod.HermesCLI._resolve_turn_agent_config(stub, "hi")
 
         assert route["runtime"]["provider"] == "openrouter"
         assert route.get("request_overrides") is None
@@ -329,27 +296,10 @@ class TestAnthropicFastMode(unittest.TestCase):
             acp_command=None,
             acp_args=[],
             _credential_pool=None,
-            _smart_model_routing={},
             service_tier="priority",
         )
 
-        original_runtime = {
-            "api_key": "***",
-            "base_url": "https://api.anthropic.com",
-            "provider": "anthropic",
-            "api_mode": "anthropic_messages",
-            "command": None,
-            "args": [],
-            "credential_pool": None,
-        }
-
-        with patch("agent.smart_model_routing.resolve_turn_route", return_value={
-            "model": "claude-opus-4-6",
-            "runtime": dict(original_runtime),
-            "label": None,
-            "signature": ("claude-opus-4-6", "anthropic", "https://api.anthropic.com", "anthropic_messages", None, ()),
-        }):
-            route = cli_mod.HermesCLI._resolve_turn_agent_config(stub, "hi")
+        route = cli_mod.HermesCLI._resolve_turn_agent_config(stub, "hi")
 
         assert route["runtime"]["provider"] == "anthropic"
         assert route["request_overrides"] == {"speed": "fast"}