Add Amharic search normalization for improved recall

[flavnat]

Summary

This PR integrates Amharic search normalization logic into the toolkit. It enhances search recall by handling common spelling variations in Amharic.

Changes

• New Feature: Added Search class in src/search.ts with normalize() method.
  • Homophone Normalization: Standardizes characters with same/similar sounds (e.g., ሐ, ኀ -> ሀ; ሠ -> ሰ).
  • Labialized Normalization: Aligns labialized sequences (e.g., ፍዋ -> ፏ).
• Configuration: Updated tsconfig.json module setting to NodeNext to fix build errors.
• Tests: Added tests/search.test.js covering homophone and labialized cases.

Checklist

• Build passes (pnpm run build)
• Tests pass (pnpm test)