feat(learn): Minimalist memory format v3.0 - 60% size reduction

BREAKING CHANGE: New compact entry format
- Header: `## {P|G}: {Title}` (P=Pattern, G=Gotcha)
- Metadata: `@YYYY-MM-DD #tag1 #tag2 | source:confidence[:reinforced]`
- Max 3 inline tags, no separators, no statistics section

Removed verbose fields: Discovered, Source, Confidence, Trigger
Statistics now calculated dynamically by /learn:status

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

.claude-plugin/marketplace.json

@@ -10,9 +10,9 @@
     {
       "name": "learn",
       "source": "./plugins/learn",
-      "description": "Domain-based memory with selective saving, signal detection, and memory hygiene",
-      "version": "2.2.0",
-      "keywords": ["learn", "memory", "patterns", "gotchas", "domains", "cleanup", "hygiene"]
+      "description": "Minimalist memory format with domain-based storage and signal detection",
+      "version": "3.0.0",
+      "keywords": ["learn", "memory", "patterns", "gotchas", "domains", "minimalist"]
     }
   ]
 }