fix(apple-notes): use full note title from body

[markoub]

Summary

• use the first line from decoded Apple Notes content as the imported note title
• fall back to the existing database title when the decoded content has no usable title line
• add unit coverage for long titles, line endings, trimming, and fallback behavior

Closes #541

Validation

• pnpm install --frozen-lockfile
• pnpm exec tsx --test tests/apple-notes/title.test.ts
• pnpm exec eslint src/formats/apple-notes.ts src/formats/apple-notes/title.ts tests/apple-notes/title.test.ts
• pnpm run test
• pnpm run build
• git diff --check origin/master...HEAD