chore: untrack non-build files — personal config, audit docs, design plans

config/config.yaml was gitignored but still tracked, so personal config
changes kept flowing into the repo; git rm --cached honours the existing
intent. Audit reports/plans and historical design docs stay local but
leave the repo. .gitignore extended for local tooling artifacts
(.sota/, graphify-out/, .claude/agents|skills/).

Files remain on disk and in git history; only HEAD is slimmed.

Author: dervish666

.gitignore

@@ -14,3 +14,17 @@ venv/
 data/
 .worktrees/
 config/config.yaml
+
+# Local tooling artifacts (not part of the build)
+.sota/
+graphify-out/
+.claude/agents/
+.claude/skills/
+
+# Internal working docs (audits, design plans) — kept locally, not shipped
+audit-plans/
+audit-reports/
+AUDIT_FINDINGS.md
+docs/audit-report-*.md
+docs/plans/
+docs/superpowers/