feat(framework): add defineHandler curried API (#10)

[qantrepreneur]

Summary

• Implement defineHandler with curried defineHandler("/path")({ GET, POST, ... }) signature for API routes
• Supports all HTTP methods (GET, POST, PUT, PATCH, DELETE) with typed params inferred from RouteMap
• Runtime behavior is identity (returns config unchanged); type-level only for param inference
• 7 tests covering runtime identity, all HTTP methods, optional methods, typed params, async handlers, and paramless routes

Test plan

• pnpm --filter @sundayceo/framework test — all 16 tests pass (9 existing + 7 new)
• pnpm --filter @sundayceo/framework check-types — no type errors
• pnpm lint — no lint errors
• pnpm format — all files formatted

Closes #10

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