feat: 实现笔临 P0/P1 Electron 桌面应用 v0.1.0

交付写作核心（TipTap、自动保存、分卷分章）、Onboarding、7 主题与双语 i18n、快捷键设置；主进程使用 node:sqlite；补全 Vitest 与 Playwright E2E；统一 design/ 目录并移除 desigin 拼写错误路径。

Co-authored-by: Cursor <cursoragent@cursor.com>

src/main/db/schema-v1.sql

@@ -0,0 +1,28 @@
+CREATE TABLE IF NOT EXISTS schema_version (
+    version     INTEGER PRIMARY KEY,
+    applied_at  TEXT NOT NULL DEFAULT (datetime('now')),
+    description TEXT
+);
+
+CREATE TABLE IF NOT EXISTS volumes (
+    id          TEXT PRIMARY KEY,
+    name        TEXT NOT NULL,
+    description TEXT DEFAULT '',
+    sort_order  INTEGER NOT NULL DEFAULT 0,
+    created_at  TEXT NOT NULL DEFAULT (datetime('now')),
+    updated_at  TEXT NOT NULL DEFAULT (datetime('now'))
+);
+
+CREATE TABLE IF NOT EXISTS chapters (
+    id          TEXT PRIMARY KEY,
+    volume_id   TEXT,
+    title       TEXT NOT NULL DEFAULT '',
+    content     TEXT NOT NULL DEFAULT '',
+    status      TEXT NOT NULL DEFAULT 'draft',
+    word_count  INTEGER NOT NULL DEFAULT 0,
+    sort_order  INTEGER NOT NULL DEFAULT 0,
+    cursor_offset INTEGER DEFAULT 0,
+    created_at  TEXT NOT NULL DEFAULT (datetime('now')),
+    updated_at  TEXT NOT NULL DEFAULT (datetime('now')),
+    FOREIGN KEY (volume_id) REFERENCES volumes(id) ON DELETE SET NULL
+);