feat: add paper/ LaTeX draft, English data scripts, update progress docs

- paper/: 22-page LaTeX framework (7/10 sections complete, compiles cleanly)
  main.tex + 10 section files + refs.bib + compiled PDF (329KB)
- code/scripts/: three English dataset generation & merging scripts
  generate_english.py / generate_english_targeted.py / merge_v5.py
- CLAUDE.md: update paper writing status, add paper/ file map entry
- state.md: add section 8 paper writing progress (2026-05-15)
- .gitignore: add LaTeX build artifact exclusion rules

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.gitignore

@@ -51,3 +51,14 @@ Thumbs.db
 # === 密钥 ===
 .env
 *.env
+
+# === LaTeX 编译产物 ===
+paper/*.aux
+paper/*.bbl
+paper/*.blg
+paper/*.log
+paper/*.toc
+paper/*.out
+paper/*.fls
+paper/*.fdb_latexmk
+paper/*.synctex.gz