feat: 内置阅读器、批注笔记与 AI 助手，发布 1.3.0

新增 PDF/EPUB/MOBI/AZW 内置阅读器，PDF 分段读取支持超大文件，
批注、读书与画布笔记、封面生成与本地导入。AI 助手支持三种协议、
图像上下文与安全 Markdown 渲染，上下文范围改为 选中/当前页/全文，
页面与全文无需选中文本即可发送，全文会提示可能超出模型限制。

便携版输出目录固定为 PeopleLib-windows-x64，不再随版本号变化，
避免升级后 data/ 被遗留在旧目录。

Co-authored-by: factory-droid[bot] <138933559+factory-droid[bot]@users.noreply.github.com>

src/reader/window.js

@@ -0,0 +1,167 @@
+// 阅读器独立窗口的生命周期管理。
+// 全局只保留一个阅读器窗口，书籍通过窗口内标签切换，避免同一 PDF 出现两个并发编辑器。
+
+const path = require('path');
+const { pathToFileURL } = require('url');
+const { BrowserWindow } = require('electron');
+
+let readerWindow = null;
+let rendererReady = false;
+let pendingMessages = [];
+let closeAllowed = false;
+let closePending = false;
+let closeTimer = null;
+
+function alive(win) {
+  return !!win && !win.isDestroyed();
+}
+
+function get() {
+  if (alive(readerWindow)) return readerWindow;
+  readerWindow = null;
+  return null;
+}
+
+function sendEntry(win, channel, payload) {
+  if (!rendererReady) {
+    pendingMessages.push([channel, payload]);
+    return;
+  }
+  win.webContents.send(channel, payload);
+}
+
+function markReady(webContents) {
+  const win = get();
+  if (!win || win.webContents.id !== webContents.id) return false;
+  rendererReady = true;
+  const messages = pendingMessages;
+  pendingMessages = [];
+  for (const [channel, payload] of messages) {
+    if (alive(win)) win.webContents.send(channel, payload);
+  }
+  return true;
+}
+
+function isReady(win) {
+  return alive(win) && win === get() && rendererReady;
+}
+
+function open(entryId, rootDir, fileIndex, locator, uiTheme = 'dark') {
+  const existing = get();
+  if (existing) {
+    if (existing.isMinimized()) existing.restore();
+    const payload = {
+      entryId: String(entryId),
+      fileIndex: Number.isInteger(fileIndex) ? fileIndex : null
+    };
+    if (locator && typeof locator === 'object') payload.locator = locator;
+    sendEntry(existing, 'reader:openEntry', payload);
+    existing.focus();
+    return existing;
+  }
+
+  readerWindow = new BrowserWindow({
+    width: 1180,
+    height: 900,
+    minWidth: 760,
+    minHeight: 540,
+    frame: false,
+    backgroundColor: '#141414',
+    icon: path.join(
+      rootDir,
+      'icons',
+      'dist',
+      uiTheme === 'light' ? 'book-ai-light.ico' : 'book-ai-dark.ico'
+    ),
+    title: 'PeopleLib',
+    webPreferences: {
+      preload: path.join(rootDir, 'preload.js'),
+      contextIsolation: true,
+      nodeIntegration: false,
+      // 重排图书正文来自不可信来源，即使已净化也不给它任何 Node 能力
+      sandbox: false,
+      spellcheck: false
+    }
+  });
+  rendererReady = false;
+  pendingMessages = [];
+  closeAllowed = false;
+  closePending = false;
+  if (closeTimer) clearTimeout(closeTimer);
+  closeTimer = null;
+
+  readerWindow.webContents.setWindowOpenHandler(() => ({ action: 'deny' }));
+  readerWindow.webContents.on('will-navigate', (event, url) => {
+    const expected = pathToFileURL(path.join(rootDir, 'src', 'ui', 'reader.html')).href;
+    if (!String(url).startsWith(expected)) event.preventDefault();
+  });
+
+  const query = { entryId: String(entryId) };
+  if (Number.isInteger(fileIndex)) query.fileIndex = String(fileIndex);
+  if (locator && typeof locator === 'object') query.locator = JSON.stringify(locator);
+  readerWindow.loadFile(path.join(rootDir, 'src', 'ui', 'reader.html'), { query });
+
+  readerWindow.on('close', (event) => {
+    if (closeAllowed || !alive(readerWindow)) return;
+    event.preventDefault();
+    if (closePending) return;
+    closePending = true;
+    sendEntry(readerWindow, 'reader:prepareClose', null);
+    closeTimer = setTimeout(() => {
+      const win = get();
+      if (win) win.destroy();
+    }, 10000);
+  });
+  readerWindow.on('closed', () => {
+    readerWindow = null;
+    rendererReady = false;
+    pendingMessages = [];
+    closeAllowed = false;
+    closePending = false;
+    if (closeTimer) clearTimeout(closeTimer);
+    closeTimer = null;
+  });
+  return readerWindow;
+}
+
+function closeFor(entryId) {
+  const win = get();
+  if (win) sendEntry(win, 'reader:closeEntry', String(entryId));
+}
+
+function purgeFor(entryId, requestId) {
+  const win = get();
+  if (win) {
+    sendEntry(win, 'reader:purgeEntry', {
+      entryId: String(entryId),
+      requestId: String(requestId)
+    });
+  }
+  return !!win;
+}
+
+function shutdownReady(webContents) {
+  const win = get();
+  if (!win || win.webContents.id !== webContents.id || !closePending) return false;
+  if (closeTimer) clearTimeout(closeTimer);
+  closeTimer = null;
+  closeAllowed = true;
+  closePending = false;
+  win.close();
+  return true;
+}
+
+function fromWebContents(wc) {
+  const win = get();
+  return win && win.webContents.id === wc.id ? 'reader' : null;
+}
+
+function all() {
+  const win = get();
+  return win ? [win] : [];
+}
+
+module.exports = {
+  open, get, closeFor, purgeFor, fromWebContents, all,
+  markReady, isReady, shutdownReady
+};