Add PostToolUse hook for automatic formatting (#563)

Added a PostToolUse hook that automatically runs `bun run format` after
Edit, Write, or MultiEdit operations, similar to the Python SDK's ruff
formatting hook. This ensures code is automatically formatted whenever
changes are made.

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

Co-authored-by: Claude <noreply@anthropic.com>

.claude/settings.json

@@ -0,0 +1,15 @@
+{
+  "hooks": {
+    "PostToolUse": [
+      {
+        "hooks": [
+          {
+            "type": "command",
+            "command": "bun run format"
+          }
+        ],
+        "matcher": "Edit|Write|MultiEdit"
+      }
+    ]
+  }
+}