Improves column key extraction in header drawer

Enhances column key retrieval to use consistent key format
Adds null check for filter template to prevent potential errors
Uses buildKeyFromColumn() for more robust key generation

.claude/settings.local.json

@@ -12,7 +12,8 @@
       "Bash(npm install:*)",
       "WebFetch(domain:raw.githubusercontent.com)",
       "Bash(npm run css:analyze:*)",
-      "Bash(npm run test:run:*)"
+      "Bash(npm run test:run:*)",
+      "Bash(cd:*)"
     ],
     "deny": [],
     "ask": []