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.

hermes_cli/config.py

@@ -691,9 +691,18 @@ DEFAULT_CONFIG = {
     #   See: https://openrouter.ai/docs/guides/features/response-caching
     # response_cache_ttl: how long cached responses remain valid, in seconds (1-86400).
     #   Default 300 (5 minutes). Only used when response_cache is enabled.
+    # min_coding_score: knob for the openrouter/pareto-code router (0.0-1.0).
+    #   Only applied when model.model is "openrouter/pareto-code". Higher
+    #   values route to stronger (more expensive) coders; lower values open
+    #   up cheaper, faster options. Default 0.65 lands on the mid-tier
+    #   coder on the current Pareto frontier. Empty string = let OpenRouter
+    #   pick the strongest available coder (router's documented default
+    #   when the plugins block is omitted).
+    #   See: https://openrouter.ai/docs/guides/routing/routers/pareto-router
     "openrouter": {
         "response_cache": True,
         "response_cache_ttl": 300,
+        "min_coding_score": 0.65,
     },
 
     # AWS Bedrock provider configuration.