feat(openrouter): wire Pareto Code router with min_coding_score knob (#22838)

Pick openrouter/pareto-code as your model and OpenRouter auto-routes each
request to the cheapest model meeting your coding-quality bar (ranked by
Artificial Analysis). The new openrouter.min_coding_score config key (0.0-1.0,
default 0.65) tunes the floor.

- hermes_cli/models.py: add openrouter/pareto-code to OPENROUTER_MODELS so
  it shows up in the picker with a description
- hermes_cli/config.py: add openrouter.min_coding_score (default 0.65 — lands
  on a mid-tier coder on the current Pareto frontier)
- plugins/model-providers/openrouter: emit extra_body.plugins =
  [{id: pareto-router, min_coding_score: X}] when model is openrouter/pareto-code
  AND the score is a valid float in [0.0, 1.0]
- agent/transports/chat_completions.py: same emission on the legacy flag
  path (when no provider profile is loaded)
- run_agent.py: openrouter_min_coding_score kwarg + storage; plumbed into
  both build_kwargs() invocations and the context-summary extra_body path
- cli.py: read openrouter.min_coding_score once at init, validate float in
  [0,1], pass to AIAgent constructions (CLI + background-task paths)
- cron/scheduler.py, batch_runner.py, tools/delegate_tool.py,
  tui_gateway/server.py: propagate the kwarg (mirrors providers_order
  plumbing — subagents inherit, cron/batch read from config)
- tests: profile-level + transport-level coverage of the model gating,
  unset/empty/out-of-range handling, and the legacy flag path
- docs: new 'OpenRouter Pareto Code Router' section in providers.md

Verified end-to-end against api.openrouter.ai: at score=0.65 we land on a
mid-tier coder, at omission we get the strongest. Score is silently dropped
on any model other than openrouter/pareto-code, so it's safe to leave set.

plugins/model-providers/openrouter/__init__.py

@@ -46,6 +46,23 @@ class OpenRouterProfile(ProviderProfile):
         prefs = context.get("provider_preferences")
         if prefs:
             body["provider"] = prefs
+
+        # Pareto Code router — model-gated. The plugins block is only
+        # meaningful for openrouter/pareto-code; sending it on any other
+        # model has no documented effect and would be confusing in logs.
+        # See: https://openrouter.ai/docs/guides/routing/routers/pareto-router
+        model = (context.get("model") or "")
+        if model == "openrouter/pareto-code":
+            score = context.get("openrouter_min_coding_score")
+            if score is not None and score != "":
+                try:
+                    score_f = float(score)
+                except (TypeError, ValueError):
+                    score_f = None
+                if score_f is not None and 0.0 <= score_f <= 1.0:
+                    body["plugins"] = [
+                        {"id": "pareto-router", "min_coding_score": score_f}
+                    ]
         return body
 
     def build_api_kwargs_extras(