feat: add Feishu release notification and bilingual highlight summary workflow

[yaojin3616]

Summary

• Reference CoAlign project's release notification workflow to add complete Feishu release notification automation for DSH Desktop.
• .github/scripts/feishu_release_notes.py:
  • Automatically compares the released tag against the previous stable tag to extract git commit subjects, commit bodies, diff statistics, and bounded code diffs.
  • Generates polished, user-facing bilingual release highlights (Chinese + English) categorized into 2-5 product themes.
  • Validates markdown structure strictly for Feishu interactive cards.
  • Supports sending interactive cards directly via webhook.
• .github/workflows/release.yml:
  • Adds Feishu release note generation and notification steps in the publish job after release assets are built, signed, and mirrored.
• Unit Tests:
  • Added test/feishu-release-notes.test.ts verifying prompt building, validation, deterministic fallback generation, and workflow definitions.

Verification

• npm run typecheck passed
• npm test passed (30 test suites, 188 tests)
• npm run build passed