fix(cli): remove hardcoded tool disabling from CLI agents

The extra system prompt was unconditionally appending "Tools are
disabled in this session. Do not call tools." which prevented all
CLI agents from using tools they had available.

src/agents/cli-runner.ts

@@ -65,12 +65,7 @@ export async function runCliAgent(params: {
   const normalizedModel = normalizeCliModel(modelId, backend);
   const modelDisplay = `${params.provider}/${modelId}`;
 
-  const extraSystemPrompt = [
-    params.extraSystemPrompt?.trim(),
-    "Tools are disabled in this session. Do not call tools.",
-  ]
-    .filter(Boolean)
-    .join("\n");
+  const extraSystemPrompt = params.extraSystemPrompt?.trim();
 
   const sessionLabel = params.sessionKey ?? params.sessionId;
   const { contextFiles } = await resolveBootstrapContextForRun({