Add npm run typecheck as Stop hook in Claude settings

Runs a full project typecheck at the end of each Claude turn so type
errors surface as feedback before the next message.

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

.claude/settings.json

@@ -10,6 +10,16 @@
           }
         ]
       }
+    ],
+    "Stop": [
+      {
+        "hooks": [
+          {
+            "type": "command",
+            "command": "npm run typecheck 2>&1"
+          }
+        ]
+      }
     ]
   }
 }