chore: add project config, Claude instructions, and reference docs

- CLAUDE.md: project guidance for Claude Code (build commands, conventions,
  editing rules, CI notes)
- AGENTS.md: agent-level task conventions for autonomous editing sessions
- .claude/: skills, memory, and settings for Claude Code integration
- docs/: research-backed LaTeX reference examples (small, medium, large-doc
  templates with latexmkrc, local .sty, CI workflow)

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

docs/examples/large-doc/.github/workflows/latex.yml

@@ -0,0 +1,17 @@
+name: build-latex
+
+on:
+  push:
+  pull_request:
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Compile LaTeX
+        uses: xu-cheng/latex-action@v4
+        with:
+          root_file: src/main.tex
+          work_in_root_file_dir: true
+          latexmk_use_lualatex: true