pin all CLI installations to explicit versions and use pro models by default (#283)

* pin all CLI installations to explicit versions and use pro models by default

- codex: pin @openai/codex to 0.101.0 (was "latest")
- opencode: pin opencode-ai to 1.1.56 (was "latest")
- gemini: pin gemini-cli to v0.28.2 via new tag param on installFromGithub
- cursor: pin to 2026.01.28-fd13201 via direct tarball download (replaces curl install script)
- add installFromDirectTarball to install.ts for versioned tarball URLs
- gemini auto effort now uses pro-preview instead of flash-preview
- test runner model overrides updated to use pro-preview consistently

Co-authored-by: Cursor <cursoragent@cursor.com>

* increase activity timeout

* fix delegation timeout

---------

Co-authored-by: Cursor <cursoragent@cursor.com>

agents/claude.ts

@@ -139,6 +139,7 @@ export const claude = agent({
       cwd: process.cwd(),
       env: process.env,
       stdio: ["ignore", "pipe", "pipe"],
+      activityTimeout: 0, // disabled: process-level timeout in main.ts handles this (subprocess timeout would kill orchestrator during delegation)
       onStdout: async (chunk) => {
         finalOutput += chunk;