chore: gitignore internal dev artifacts (untrack from public repo)

Untracked from public repo (still present locally for development):
- CLAUDE.md (AI workspace instructions)
- ROADMAP.md (project status tracking)
- HANDOFF.md (session handoff)
- WAY_OF_WORK.md (methodology)
- LESSONS.md (internal log)
- DECISIONS.md (internal architectural decisions)
- REQUIREMENTS.md (internal scope)
- OPEN-QUESTIONS.md (internal questions log)
- START-PROMPT.md (session starter)
- docs/masterplan/ (internal planning)
- docs/research/ (internal research)

Kept public (consumer-facing):
- README.md, CHANGELOG.md, INDEX.md, CONTRIBUTING.md, INSTALL.md, USAGE.md, SECURITY.md, AGENT-SKILLS-STANDARD.md, SOURCES.md, LICENSE
- docs/validation/audit-report.md
- skills/source/**/*.md (168 skill files)

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

Author: FreekHeijting

.gitignore

@@ -5,6 +5,19 @@ CLAUDE.local.md
 .claude/
 *.code-workspace
 
+# Internal dev artifacts (kept local, not published)
+CLAUDE.md
+ROADMAP.md
+HANDOFF.md
+WAY_OF_WORK.md
+LESSONS.md
+DECISIONS.md
+REQUIREMENTS.md
+OPEN-QUESTIONS.md
+START-PROMPT.md
+docs/masterplan/
+docs/research/
+
 # tmux-orchestration runtime state
 state/
 .tmo/