fix(executors): strip params unsupported by provider/model

Add config-driven stripUnsupportedParams helper and use it in the default and github executors. Removes the deprecated temperature param for claude-opus-4 models (Anthropic 400) and consolidates github's scattered capability checks into one rule table.

Fixes #1748

Co-Authored-By: fjia <fjia@suntekcorps.com>
Co-authored-by: Cursor <cursoragent@cursor.com>

open-sse/translator/concerns/paramSupport.js

@@ -0,0 +1,31 @@
+// Strip request params a given provider/model rejects upstream (e.g. HTTP 400).
+// Config-driven: add a rule instead of scattering `delete body.x` across executors.
+
+// Each rule: optional provider, regex match on model, list of params to drop.
+// A param is removed only when it is present (!== undefined).
+const STRIP_RULES = [
+  // claude-opus-4 series: temperature is deprecated (Anthropic 400). #1748
+  { match: /claude-opus-4/i, drop: ["temperature"] },
+  // GitHub Copilot gpt-5.4: temperature unsupported.
+  { provider: "github", match: /gpt-5\.4/i, drop: ["temperature"] },
+  // GitHub Copilot Claude (except opus/sonnet 4.6): thinking + reasoning_effort rejected. #713
+  { provider: "github", match: (m) => /claude/i.test(m) && !/claude.*(opus|sonnet).*4\.6/i.test(m), drop: ["thinking", "reasoning_effort"] },
+];
+
+// Test a rule's match (regex or predicate) against the model id.
+function matches(rule, model) {
+  return typeof rule.match === "function" ? rule.match(model) : rule.match.test(model);
+}
+
+// Remove unsupported params from body in place; returns body.
+export function stripUnsupportedParams(provider, model, body) {
+  if (!model || !body || typeof body !== "object") return body;
+  for (const rule of STRIP_RULES) {
+    if (rule.provider && rule.provider !== provider) continue;
+    if (!matches(rule, model)) continue;
+    for (const key of rule.drop) {
+      if (body[key] !== undefined) delete body[key];
+    }
+  }
+  return body;
+}