feat: add user-scoped Supabase auth

[Albert-Gao]

Summary

• add verifyUserAuth as a core helper for Supabase user JWT verification
• default user-token audience validation to authenticated and support optional user ID matching
• add Hono withSupabaseUserAuth middleware that sets a user-scoped Supabase context without creating an admin client

Why

withSupabase and createSupabaseContext always create supabaseAdmin, which requires SUPABASE_SECRET_KEY. User-facing runtime APIs often only need a verified Supabase user token and an RLS-scoped client, so this adds a narrower path that does not require secret keys in those runtimes.

Validation

• pnpm exec prettier --check src/adapters/hono/index.ts src/adapters/hono/middleware.test.ts src/adapters/hono/middleware.ts src/core/index.ts src/core/verify-user-auth.test.ts src/core/verify-user-auth.ts src/index.ts src/types.ts
• pnpm lint
• pnpm typecheck
• pnpm test
• pnpm build