refactor(onboard,init-project): migrate file paths to .claude/

Adapt the two skills that scaffold project config + the underlying
onboarder agent + the dotfiles-meta archetype folder tree to the new
governance layout. AUDIT_* files go to .claude/audits/, TODO goes to
.claude/tasks/, and .claude/memory/ is seeded from ~/.claude/templates/memory/
with all 5 registries (decisions/learnings/blockers/journal/evals).

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

lib/project-archetypes/dotfiles-meta.md

@@ -111,5 +111,7 @@ skills/            (skills custom)
 hooks/             (hooks projet, pas git)
 templates/         (templates config fournis)
 lib/               (helpers shell)
-tasks/
+.claude/tasks/
+.claude/memory/
+.claude/audits/
 ```