C04: Add Rav Kook — rabbinic-Ashkenazi hand, 4 PDM-1.0 pages

[shaypal5]

Summary

Add Rabbi Abraham Isaac Kook (1865–1935) as the third writer. Kook is the founding Chief Rabbi of British Mandatory Palestine and a prolific correspondent; four PDM-1.0 pages are already in the upstream repo. His handwriting is dense, compressed rabbinic-Ashkenazi — a genuinely different style from both Bialik and Rachel — making him a high-value third data point for style diversity.

Writer record

Field	Value
writer_id	avraham_yitzhak_kook
display_name	Abraham Isaac Kook
also_known_as	Rav Kook, HaRav Kook, אברהם יצחק הכהן קוק, Avraham Yitzchak HaCohen Kook
born / died	1865 / 1935 — PDM in all life+70 jurisdictions
scripts_written	Hebr
languages_written	he, yi, ar (classical)
period	1890–1935
VIAF	https://viaf.org/viaf/95177956/
Wikipedia	https://en.wikipedia.org/wiki/Abraham_Isaac_Kook

Upstream sources

entry_id	license	Notes
commons__rav_kook_shemitah_letter__p0001	PDM-1.0	High-resolution scan — start here
commons__rav_kook_letter_03__p0001	PDM-1.0	Letter to Ben-Zion
commons__kook_letter_12_tammuz_1928__p0001	PDM-1.0	Dated 22 June 1928
commons__chief_rabbinate_letter_1921__p0001	PDM-1.0	Chief Rabbinate proclamation, 1921

All four: rights_basis: public_domain, attribution_required: false.

Acceptance criteria

• New avraham_yitzhak_kook writer row in writers.jsonl with status: verified
• At least 15 distinct letter forms added
• All entries pass python3 scripts/validate_indexes.py --upstream-path <upstream>
• python3 scripts/generate_release_artifacts.py --check passes
• python3 -m pytest passes

Ingest notes

• Start with commons__rav_kook_shemitah_letter__p0001 (explicitly noted as high-resolution in the upstream source description)
• Rabbinic handwriting is typically compressed and ligature-heavy; final forms (kaf_final, mem_final, nun_final, pe_final, tsadi_final) appear distinctively at line ends and are worth careful attention
• ayin and tet take stylised rabbinic forms that can look unfamiliar — document in quality.notes where relevant
• letter.style should reflect rabbinic Ashkenazi cursive
• entry_id format: avraham_yitzhak_kook__<letter_name>__v0001
• File path: data/letters/avraham_yitzhak_kook/<letter_name>/avraham_yitzhak_kook__<letter_name>__v0001.<ext>