feat: 添加密码管理功能，包括 API、数据库支持和前端界面

apps/extension/src/background.js

@@ -0,0 +1,21 @@
+const PENDING_KEY = "bb_pending_credential";
+const PENDING_TAB_KEY = "bb_pending_tab_id";
+
+function openPopup() {
+  if (typeof chrome === "undefined" || !chrome.action?.openPopup) return;
+  chrome.action.openPopup().catch(() => {
+    // ignore if popup cannot be opened (no user gesture)
+  });
+}
+
+chrome.runtime.onMessage.addListener((msg, sender) => {
+  if (!msg || msg.type !== "CREDENTIAL_CAPTURED") return;
+
+  const payload = msg.payload || {};
+  chrome.storage.local.set({
+    [PENDING_KEY]: payload,
+    [PENDING_TAB_KEY]: sender?.tab?.id || null
+  }, () => {
+    openPopup();
+  });
+});