feat: add model thinking level metadata

closes #3208

packages/coding-agent/src/core/extensions/types.ts

@@ -1359,6 +1359,8 @@ export interface ProviderModelConfig {
 	baseUrl?: string;
 	/** Whether the model supports extended thinking. */
 	reasoning: boolean;
+	/** Maps pi thinking levels to provider/model-specific values; null marks a level unsupported. */
+	thinkingLevelMap?: Model<Api>["thinkingLevelMap"];
 	/** Supported input types. */
 	input: ("text" | "image")[];
 	/** Cost per token (for tracking, can be 0). */