feat: add eval framework for installer agent testing

[nicknisi]

Summary

• Add comprehensive eval framework with fixtures for all 5 frameworks × 3 states (15 scenarios)
• Wire AgentExecutor to use Claude Agent SDK directly with direct auth mode
• Add retry logic, debug tooling, and history tracking for eval runs

Why

Need automated testing to validate installer agent behavior across different project configurations before releases.

Notes

• Run evals with pnpm eval --framework=nextjs --state=fresh
• Requires ANTHROPIC_API_KEY in .env.local
• Fixtures cover fresh projects, existing apps, and apps with competing auth (Auth0)

[nicknisi]

Example run:

Framework	State
Next.js	Fresh

> tsx tests/evals/index.ts --framework=nextjs --verbose --keepOnFail --state=fresh


Running: nextjs/fresh
  Installing dependencies...
[dotenv@17.2.3] injecting env (2) from .env.local -- tip: ⚙️  load multiple .env files with { path: ['.env.local', '.env'] }
  Initializing agent for nextjs...
  Tool: Skill
  Agent: I'll start by fetching the SDK documentation from the README, which is the source of truth....
  Tool: WebFetch
  Agent: Now let me validate the project structure and check the existing environment variables....
  Tool: Glob
  Tool: Read
  Tool: Read
  Tool: Glob
  Agent: Let me also check the existing app structure:...
  Tool: Glob
  Tool: Read
  Tool: Read
  Tool: TodoWrite
  Agent: Now let me proceed with the integration. First, I'll add the missing environment variable and instal...
  Tool: Edit
  Tool: Bash
  Agent: Let me check if there's a pnpm or yarn lockfile to determine the correct package manager:...
  Tool: Bash
  Tool: Bash
  Tool: Bash
  Tool: TodoWrite
  Agent: Now let me verify the SDK is installed and create the middleware. Since this is Next.js 14, I'll cre...
  Tool: Bash
  Agent: Now let me create the middleware, callback route, update layout, and update the page:...
  Tool: Write
  Tool: Bash
  Tool: Write
  Tool: TodoWrite
  Agent: Now let me update the layout with AuthKitProvider and the page with auth UI:...
  Tool: Write
  Tool: Write
  Tool: TodoWrite
  Agent: Now let me run the verification checklist and build:...
  Tool: Bash
  Tool: Bash
  Tool: Bash
  Agent: All verification checks pass. Now let's run the build:...
  Tool: Bash
  Agent: Let me check the correct import paths from the SDK:...
  Tool: Bash
  Tool: Bash
  Tool: Bash
  Agent: I see - the SDK doesn't have `getUser` and `AuthKitProvider` in the main exports. Let me check the c...
  Tool: Bash
  Tool: Bash
  Agent: I see - `AuthKitProvider` is in `@workos-inc/authkit-nextjs/components`, and I need to use `withAuth...
  Tool: Bash
  Tool: Bash
  Tool: Bash
  Agent: Now I understand. The SDK uses `withAuth` instead of `getUser`. Let me update the files with the cor...
  Tool: Write
  Tool: Write
  Agent: Now let's run the build again:...
  Tool: Bash
  Agent: The build succeeded. Let me update the todo list to show completion:...
  Tool: TodoWrite
  Agent: I've successfully integrated WorkOS AuthKit into your Next.js application. Here's a summary of what ...
✓ PASSED

Results saved to: /Users/nicknisi/Developer/cli/prompt-improvements/tests/eval-results/2026-02-01T05-39-28-884Z.json

┌─────────────────┬─────────┬──────────┬───────────────┐
│ Framework       │  Fresh  │ Existing │ Existing+Auth │
├─────────────────┼─────────┼──────────┼───────────────┤
│ nextjs          │   ✓   │   -     │   -        │
│ react           │   -   │   -     │   -        │
│ react-router    │   -   │   -     │   -        │
│ tanstack-start  │   -   │   -     │   -        │
│ vanilla-js      │   -   │   -     │   -        │
└─────────────────┴─────────┴──────────┴───────────────┘

Results: 1/1 passed (100.0%)
pnpm eval --framework=nextjs --verbose --keepOnFail --state=fresh  66.79s user 23.09s system 32% cpu 4:39.04 total