feat(data): add Rachel Bluwstein — 24 letter crops from Aqara 1928 (C03)

[shaypal5]

Summary

• Adds rachel_bluwstein as the second writer in data/index/writers.jsonl (status: verified; PDM-1.0 upstream scans)
• Crops 24 Hebrew letter forms (21 distinct letter types, 3 with 2 variants each) from the PDM-1.0 scan of her 1928 autograph manuscript of 'Aqara' (commons__rachel_aqara_1928__p0001, 653×1024 px)
• Letters covered: alef, ayin, bet, dalet, gimel, he, het, kaf, lamed ×2, mem ×2, nun, nun_final, qof, resh, samekh, shin, tav, tet, vav, yod ×2, zayin
• Regenerates NOTICE.md, CITATION.cff, datapackage.json

Closes #6

Validation

ok: 2 writers, 49 entries, 49 files verified, 49 upstream-cross-checked
62 passed, 1 skipped
git diff --check: (clean)
generate_release_artifacts.py --check: artefacts unchanged after generation

Test plan

• python3 scripts/validate_indexes.py --upstream-path ../public-domain-hand-written-hebrew-scans → ok: 2 writers, 49 entries, 49 files verified, 49 upstream-cross-checked
• python3 scripts/generate_release_artifacts.py → artefacts written; --check form confirms no drift
• python3 -m pytest → 62 passed, 1 skipped
• git diff --check → clean
• 24 PNG files tracked via Git LFS in data/letters/rachel_bluwstein/
• All entries reference upstream commit 0e162a78 and upstream SHA256 verified against live entries.jsonl

🤖 Generated with Claude Code