hybrid: replace guessed OpenRouter Qwen prices with list prices

The Qwen3.5/3.6 entries were active-param-scaled guesses with a comment saying
to verify them before trusting the cost-aware reward. Verified against
openrouter.ai: every one of them was low on output, by 1.5x (9B) to 5.2x
(27B), with the 122B off by 3.5x. The reward reads PRICES directly, so it has
been undercharging the mid and large Qwen experts the whole time.

qwen3.6-27b is not listed on OpenRouter; charge it at qwen3.5-27b's quote,
which is the nearest real one.

src/openjarvis/agents/hybrid/_prices.py

@@ -35,13 +35,16 @@ PRICES: dict[str, tuple[float, float]] = {
     "qwen/qwen3-32b": (0.10, 0.30),
     "meta-llama/llama-3.3-70b-instruct": (0.13, 0.39),
     # OpenRouter slugs for the orchestrator's local-OSS class when routed via
-    # OpenRouter instead of self-hosted vLLM. ESTIMATES — no public list price
-    # exists yet for these Qwen3.5/3.6 builds; scaled by active-param size.
-    # VERIFY against openrouter.ai before trusting the cost-aware reward numbers.
-    "qwen/qwen3.5-9b": (0.05, 0.10),
-    "qwen/qwen3.6-27b": (0.10, 0.30),
-    "qwen/qwen3.5-122b-a10b": (0.20, 0.60),
-    "qwen/qwen3.5-397b-a17b": (0.40, 1.20),
+    # OpenRouter instead of self-hosted vLLM. OpenRouter list price, checked
+    # 2026-07-11. These replace earlier active-param-scaled guesses that were
+    # 2-5x low on output; the cost-aware reward reads these directly, so the
+    # guesses were systematically undercharging the mid/large Qwen experts.
+    "qwen/qwen3.5-9b": (0.10, 0.15),
+    # qwen3.6-27b is not listed on OpenRouter; qwen3.5-27b is the nearest real
+    # quote and is what we charge for it.
+    "qwen/qwen3.6-27b": (0.195, 1.56),
+    "qwen/qwen3.5-122b-a10b": (0.26, 2.08),
+    "qwen/qwen3.5-397b-a17b": (0.385, 2.45),
 }
 
 # Models whose API rejects an explicit `temperature` param — callers should