refactor: reorganize directory structure into src/

Move all source code directories into src/ for cleaner project structure:
- pages/, components/, utils/, config/, providers/, types/, lib/, assets/, entrypoints/ → src/
- Use WXT srcDir config to resolve @/ alias to src/
- Update tsconfig, vitest, eslint, tailwind configs
- Remove scattered README.md files from subdirectories
- Update documentation (AGENTS.md, CODING_STANDARDS.md, README.md)
- Fix pre-existing lint error in RouterProvider.tsx

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

src/utils/messages.ts

@@ -0,0 +1,75 @@
+import { defineExtensionMessaging } from '@webext-core/messaging';
+
+export enum MessageAction {
+  RELOAD_TAB = 'reloadTab',
+  SIDE_PANEL_STATE_CHANGED = 'sidePanelStateChanged',
+  CONTEXT_MENU_CLICKED = 'contextMenuClicked',
+  RESTORE_RIGHT_CLICK = 'restoreRightClick',
+  QUERY_RIGHT_CLICK_STATUS = 'queryRightClickStatus',
+  INJECT_MAIN_WORLD_SCRIPT = 'injectMainWorldScript',
+}
+
+export interface MessageResponse {
+  success: boolean;
+  message?: string;
+  error?: string;
+}
+
+export interface ContextMenuClickedPayload {
+  featureKey: string;
+  payload: string;
+}
+
+export interface ProtocolMap {
+  [MessageAction.RELOAD_TAB](data: { tabId: number; delay?: number }): MessageResponse;
+  [MessageAction.SIDE_PANEL_STATE_CHANGED](data: { isOpen: boolean }): void;
+  [MessageAction.CONTEXT_MENU_CLICKED](data: ContextMenuClickedPayload): void;
+  [MessageAction.RESTORE_RIGHT_CLICK](data: undefined): MessageResponse & { restored: boolean };
+  [MessageAction.QUERY_RIGHT_CLICK_STATUS](
+    data: undefined,
+  ): MessageResponse & { restored: boolean };
+  [MessageAction.INJECT_MAIN_WORLD_SCRIPT](data: undefined): MessageResponse;
+}
+
+export const { sendMessage, onMessage } = defineExtensionMessaging<ProtocolMap>();
+
+export async function sendMessageToContent<K extends keyof ProtocolMap>(
+  action: K,
+  ...args: Parameters<ProtocolMap[K]>[0] extends undefined
+    ? []
+    : [data: Parameters<ProtocolMap[K]>[0]]
+): Promise<ReturnType<ProtocolMap[K]>> {
+  try {
+    const [tab] = await chrome.tabs.query({ active: true, currentWindow: true });
+    if (!tab?.id) {
+      console.warn(`[Messaging] 无法获取当前标签页，无法发送动作: ${action}`);
+      return { success: false, message: '无法获取当前标签页' } as ReturnType<ProtocolMap[K]>;
+    }
+
+    const data = args.length > 0 ? args[0] : undefined;
+
+    const response = await (
+      sendMessage as (
+        type: K,
+        data: Parameters<ProtocolMap[K]>[0],
+        arg?: number,
+      ) => Promise<ReturnType<ProtocolMap[K]>>
+    )(action, data as Parameters<ProtocolMap[K]>[0], tab.id);
+
+    return response;
+  } catch (error) {
+    const errorMsg = error instanceof Error ? error.message : String(error);
+    console.error(`[Messaging] 向内容脚本发送消息失败 [Action: ${action}]:`, errorMsg);
+
+    if (errorMsg.includes('Could not establish connection')) {
+      return { success: false, message: '无法连接到网页，请刷新页面后再试' } as ReturnType<
+        ProtocolMap[K]
+      >;
+    }
+    if (errorMsg.includes('No response')) {
+      return { success: false, message: '网页响应超时，请重试' } as ReturnType<ProtocolMap[K]>;
+    }
+
+    return { success: false, message: `通信失败: ${errorMsg}` } as ReturnType<ProtocolMap[K]>;
+  }
+}