chore(memory): L0 line-1 convention — all files start with L0 summary

Migrated all memory files to have L0 comment as first line,
consistent with upstream PAI convention.

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

memory/cog-meta/patterns.md

@@ -1,4 +1,4 @@
-# Cog — Learned Patterns
 <!-- L0: Distilled interaction and workflow rules from experience -->
+# Cog — Learned Patterns
 
 <!-- Edit in place. Distill self-observations into actionable patterns. Timeless rules only. HARD LIMIT: 110 lines / 7.5KB. -->