docs: add AI Traceability & Attribution guide

Comprehensive documentation on AI code attribution and disclosure:

- New guide: guide/ai-traceability.md (~640 lines)
  - LLVM "Human-in-the-Loop" policy (Assisted-by trailer)
  - Ghostty mandatory disclosure pattern
  - Fedora contributor accountability framework
  - git-ai tool documentation
  - PromptPwnd security vulnerability
  - Four-level disclosure spectrum
  - Implementation guides (solo, team, enterprise)

- Templates: examples/config/
  - CONTRIBUTING-ai-disclosure.md
  - PULL_REQUEST_TEMPLATE-ai.md

- Cross-references added to:
  - ultimate-guide.md (after Co-Authored-By section)
  - learning-with-ai.md (after Vibe Coding Trap)
  - security-hardening.md (See Also)
  - guide/README.md (table of contents)

- reference.yaml: 14 new entries for AI traceability topics

Source: Vibe coding needs git blame (Piotr Migdał, Jan 2026)
+ Perplexity research on LLVM, Ghostty, Fedora policies

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

examples/config/CONTRIBUTING-ai-disclosure.md

@@ -0,0 +1,68 @@
+# AI Assistance Disclosure (CONTRIBUTING.md Template)
+
+> Copy this section into your project's CONTRIBUTING.md
+
+---
+
+## AI Assistance Disclosure
+
+If you use any AI tools to help with your contribution, please disclose this
+in your pull request description.
+
+### What to Disclose
+
+| AI Usage | Example Disclosure |
+|----------|-------------------|
+| **AI-generated code** | "This PR was written primarily by Claude Code" |
+| **AI-assisted research** | "I consulted ChatGPT to understand the codebase" |
+| **AI-suggested approach** | "Copilot suggested the algorithm structure" |
+| **AI-drafted docs** | "Documentation was drafted with Claude assistance" |
+
+### What Doesn't Need Disclosure
+
+- Trivial autocomplete (single keywords, short phrases)
+- IDE syntax helpers (formatting, auto-imports)
+- Grammar/spell checking
+- Code formatting tools (prettier, black)
+
+### Why We Ask
+
+AI-generated code often requires more careful review:
+
+- May use patterns unfamiliar to the codebase
+- Could introduce subtle bugs humans wouldn't make
+- Might miss project-specific conventions
+- Sometimes "looks right" but has logical issues
+
+Disclosure helps maintainers:
+- Allocate review time appropriately
+- Know where to look more carefully
+- Provide better feedback on AI usage
+
+This is a **courtesy to reviewers**, not a judgment on AI use.
+
+### Suggested Disclosure Format
+
+In your PR description:
+
+```markdown
+## AI Assistance
+
+This PR was developed with assistance from [Tool Name].
+Specifically:
+- [What AI helped with]
+- [What you did manually]
+
+All code has been reviewed and understood by the author.
+```
+
+---
+
+## Attribution
+
+Based on policies from:
+- [Ghostty](https://github.com/ghostty-org/ghostty/blob/main/CONTRIBUTING.md)
+- [LLVM](https://llvm.org/docs/DeveloperPolicy.html)
+- [Fedora](https://docs.fedoraproject.org/en-US/project/ai-policy/)
+
+For more context, see [AI Traceability Guide](https://github.com/FlorianBruniaux/claude-code-ultimate-guide/blob/main/guide/ai-traceability.md).

examples/config/PULL_REQUEST_TEMPLATE-ai.md

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+# Pull Request Template with AI Disclosure
+
+> Save as `.github/PULL_REQUEST_TEMPLATE.md` in your repository
+
+---
+
+## Description
+
+<!-- Describe your changes in detail -->
+
+## Type of Change
+
+<!-- Check the relevant option -->
+
+- [ ] Bug fix (non-breaking change that fixes an issue)
+- [ ] New feature (non-breaking change that adds functionality)
+- [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
+- [ ] Documentation update
+- [ ] Refactoring (no functional changes)
+
+## AI Assistance
+
+<!-- Check all that apply -->
+
+- [ ] No AI tools were used for this contribution
+- [ ] AI was used for research/understanding only (no generated code)
+- [ ] AI generated some code (please specify below)
+- [ ] AI generated most of the code (please specify below)
+
+<!-- If AI was used, please specify: -->
+**AI Tool(s) Used**: <!-- e.g., Claude Code, GitHub Copilot, ChatGPT, Cursor -->
+
+**What AI Helped With**: <!-- e.g., initial implementation, tests, docs, refactoring -->
+
+## Checklist
+
+- [ ] I have reviewed all AI-generated code and understand it
+- [ ] I can answer questions about this code during review
+- [ ] My code follows the project's style guidelines
+- [ ] I have added tests that prove my fix/feature works
+- [ ] New and existing tests pass locally
+- [ ] I have updated documentation if needed
+
+## Additional Context
+
+<!-- Add any other context about the PR here -->