Add product scope & tracking docs and document auth debug endpoint

[chake111]

Motivation

• Centralize product, design, development and data upkeep by extracting product scope, event tracking, and review rules into a standalone document.
• Surface the new non-production auth debugging endpoint (GET /api/auth/debug) in the README to clarify its behavior and safety considerations.

Description

• Add docs/product-scope-and-tracking.md containing product boundaries for Home/Results/Compare, an event tracking dictionary for the iteration, phase acceptance criteria, and a 30-minute review/requirement-freeze process.
• Update README.md to reference the new product docs and to document the GET /api/auth/debug endpoint and the runtime warning messages for missing auth configuration.
• Keep logging and debug behavior notes to ensure secret values are not printed while providing configuration status (configured/missing) and NEXTAUTH_URL validation semantics.

Testing

• This is a documentation-only change and did not modify application code paths, so no automated tests were run as part of this PR.

---

Codex Task

[vercel]

The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Actions	Updated (UTC)
ai-tool-picker	Ready	Preview, Comment	Apr 20, 2026 0:34am