Revert "fix: improve GitHub Copilot integration"

This reverts commit 21a9b3b66f.

src/agents/pi-embedded-runner/model.ts

@@ -7,18 +7,9 @@ import { resolveClawdbotAgentDir } from "../agent-paths.js";
 import { DEFAULT_CONTEXT_TOKENS } from "../defaults.js";
 import { normalizeModelCompat } from "../model-compat.js";
 import { normalizeProviderId } from "../model-selection.js";
-import { resolveGithubCopilotUserAgent } from "../../providers/github-copilot-utils.js";
 
 type InlineModelEntry = ModelDefinitionConfig & { provider: string };
 
-function applyProviderModelOverrides(model: Model<Api>): Model<Api> {
-  if (model.provider === "github-copilot") {
-    const headers = { ...(model.headers ?? {}), "User-Agent": resolveGithubCopilotUserAgent() };
-    return { ...model, headers };
-  }
-  return model;
-}
-
 export function buildInlineProviderModels(
   providers: Record<string, { models?: ModelDefinitionConfig[] }>,
 ): InlineModelEntry[] {
@@ -69,7 +60,7 @@ export function resolveModel(
     if (inlineMatch) {
       const normalized = normalizeModelCompat(inlineMatch as Model<Api>);
       return {
-        model: applyProviderModelOverrides(normalized),
+        model: normalized,
         authStorage,
         modelRegistry,
       };
@@ -87,7 +78,7 @@ export function resolveModel(
         contextWindow: providerCfg?.models?.[0]?.contextWindow ?? DEFAULT_CONTEXT_TOKENS,
         maxTokens: providerCfg?.models?.[0]?.maxTokens ?? DEFAULT_CONTEXT_TOKENS,
       } as Model<Api>);
-      return { model: applyProviderModelOverrides(fallbackModel), authStorage, modelRegistry };
+      return { model: fallbackModel, authStorage, modelRegistry };
     }
     return {
       error: `Unknown model: ${provider}/${modelId}`,
@@ -95,9 +86,5 @@ export function resolveModel(
       modelRegistry,
     };
   }
-  return {
-    model: applyProviderModelOverrides(normalizeModelCompat(model)),
-    authStorage,
-    modelRegistry,
-  };
+  return { model: normalizeModelCompat(model), authStorage, modelRegistry };
 }