feat: expand to Tibetan + Theravada — 10 masters across 三大传统 (v0.4)

Adds the project's first non-Chinese masters, taking the scope from
"Chinese Buddhist" to "Buddhist" and matching the project name's
broader implication.

New masters
-----------
• prebuilt/milarepa — Tibetan Kagyu yogi (1052–1135). Sources:
  The Hundred Thousand Songs of Milarepa (mGur 'bum, BDRC W1KG14334)
  and The Life of Milarepa (rNam thar, BDRC W22272). Coverage:
  Mahāmudrā view, Naro Chodruk (name-level only — no esoteric steps),
  retreat & austerity, guru yoga, karma & purification.

• prebuilt/ajahn-chah — Thai Forest Tradition founder of Wat Pah Pong
  (1918–1992). Sources: Pali Canon (SuttaCentral SC IDs) plus
  authorized English collections Food for the Heart, A Still Forest
  Pool, Living Dhamma. Coverage: sati & satipaṭṭhāna, ānāpānasati,
  three characteristics, letting go, sīla-samādhi-paññā, middle way.

HARD-GATE additions
-------------------
• no_esoteric_instruction — Tibetan tantric practice steps (tummo,
  generation/completion stages, empowerment-required visualizations
  and mantras) are never disclosed; queries are redirected to
  qualified teachers. Boundary registered in
  scripts/validate-fidelity.py.

• No fabricated quotes for Theravāda discourses — Ajahn Chah quotes
  must trace to authorized publications; no synthesized "Ajahn Chah
  said" dialogue.

Citation system
---------------
BDRC:Wxxxxx (Tibetan canon) and SuttaCentral SC IDs are now
first-class alongside CBETA Txxnxxxx in frontmatter sources lists.
validate.py already accepts non-cbeta sources via the existing
title-or-cbeta_id check, no schema change required.

Cross-tradition compare-masters mappings
----------------------------------------
prebuilt/compare/SKILL.md gets new fallback rows for: 苦行/闭关
(xuyun + milarepa), 正念/觉知 (huineng + ajahn-chah + xuyun),
出离心/无常 (yinguang + milarepa + ajahn-chah), 三大传统对比
(huineng + milarepa + ajahn-chah), and adds milarepa to 般若/空性,
ajahn-chah to 戒律/行持.

Surface updates
---------------
• Description across package.json, .claude-plugin/{plugin,marketplace}.json,
  .cursor-plugin/plugin.json: "Chinese Buddhist" → "Buddhist",
  "8 prebuilt masters" → "10 prebuilt masters across 汉传/藏传/南传".
• README.md + README_EN.md: cross-tradition rows in the situational
  guidance table; new master cards for Milarepa and Ajahn Chah with
  appropriate provenance notes; v0.4 release banner replaces v0.3.
• SKILL.md preset list reorganized by tradition.
• CHANGELOG.md gets a [0.4.0] section.
• package.json keywords add tibetan-buddhism, theravada, bdrc,
  suttacentral.

Validation
----------
• python scripts/validate.py --strict → ✅ 11 masters pass
• python scripts/validate-fidelity.py → ✅ 11 masters validated
  (12 + 13 fidelity cases for the two new masters)
• python scripts/test-fidelity.py --all --dry-run → ✅
• pytest tests/ → ✅ 31 passed, 6 skipped

The progressive-disclosure shape of v0.3 is preserved exactly, so
the fidelity-smoke CI cost cap is unchanged.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

prebuilt/compare/SKILL.md

@@ -36,9 +36,14 @@ verified_at: 2026-04-06
 | 唯识 / 中观 / 空有 | xuanzang + kumarajiva | 唯识 vs 中观 |
 | 判教 / 圆融 / 止观 | zhiyi + fazang | 天台 vs 华严 |
 | 修行次第 / 综合法门 | ouyi + yinguang | 综合 vs 专修 |
-| 戒律 / 行持 / 日常 | xuyun + yinguang | 禅门戒律 vs 净土行持 |
-| 般若 / 空性 | kumarajiva + huineng | 中观 vs 禅宗 |
+| 戒律 / 行持 / 日常 | xuyun + yinguang + ajahn-chah | 禅门戒律 vs 净土行持 vs 上座部律仪 |
+| 般若 / 空性 | kumarajiva + huineng + milarepa | 中观 · 禅宗直指 · 大手印明空 |
 | 心识 / 阿赖耶 | xuanzang + huineng | 唯识分析 vs 禅宗直指 |
+| 苦行 / 闭关 / 山中修行 | xuyun + milarepa | 汉传禅门头陀 vs 藏传瑜伽士传统 |
+| 正念 / 观心 / 觉知 | huineng + ajahn-chah + xuyun | 禅宗自性 vs 南传 sati vs 参话头 |
+| 出离心 / 暇满 / 无常 | yinguang + milarepa + ajahn-chah | 净土 · 噶举 · 上座部三大传统对比 |
+| 上师 / 善知识 / 依止 | xuyun + milarepa | 汉传亲近善知识 vs 藏传上师瑜伽 |
+| 三大传统对比（明确要求） | huineng + milarepa + ajahn-chah | 禅 · 大手印 · 森林禅，最经典三方对照 |
 | 其他 | kumarajiva + yinguang | 中观 + 净土两大传统 |
 
 ## 工作流程