chore: .workbuddy/ 加入 .gitignore（工作区数据不入库，避免破坏静态文件清单门禁）

Author: NBL Agent

.gitignore

@@ -15,4 +15,7 @@ node_modules/
 npm-debug.log*
 
 # Playwright CLI session artifacts
-.playwright-cli/
+.playwright-cli/
+
+# WorkBuddy workspace data (memory/logs - never commit; breaks static-check file-set gate)
+.workbuddy/