fix: remove destructive cache-clear instruction from CLAUDE.md

The CLAUDE.md mandatory rule instructed clearing the plugin cache
mid-session, which breaks all MCP tools that were already loaded.
MCP tools are loaded with absolute paths to the venv, and deleting
the cache removes the venv while the session still references it.

Changes:
- CLAUDE.md: Replace "ALWAYS CLEAR CACHE" with "VERIFY AND RESTART"
- verify-hooks.sh: Change cache existence from error to info message
- DEBUGGING-CHECKLIST.md: Add section explaining cache timing

Fixes #145

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

scripts/verify-hooks.sh

@@ -15,11 +15,11 @@ for f in $(find ~/.claude -name "hooks.json" 2>/dev/null); do
     fi
 done
 
-# Check cache specifically
+# Note about cache (informational only - do NOT clear mid-session)
 if [ -d ~/.claude/plugins/cache/leo-claude-mktplace ]; then
-    echo "❌ CACHE EXISTS: ~/.claude/plugins/cache/leo-claude-mktplace"
-    echo "   Run: rm -rf ~/.claude/plugins/cache/leo-claude-mktplace/"
-    FAILED=1
+    echo "ℹ️  Cache exists: ~/.claude/plugins/cache/leo-claude-mktplace"
+    echo "   (This is normal - do NOT clear mid-session or MCP tools will break)"
+    echo "   To apply plugin changes: restart Claude Code session"
 fi
 
 # Verify installed hooks are command type