feat: 迁移前端构建从 Bun fullstack 到 Vite

前端性能问题根因在于 Bun bundler 无法有效 code split、CSS
tree-shake 和产出优化的前端资源。经多轮 Bun 原生优化尝试
均无明显效果后，决定将前端构建迁回 Vite。

主要变更：

- 前端构建：从 Bun HTML import bundling 切换为 Vite build
  （Rolldown code splitting、vendor chunk、CSS 优化）
- 开发模式：从 Bun fullstack 单进程 HMR 切换为 Vite dev
  server + Bun API server 双进程（:5173 + :3000）
- 生产构建：三步流水线（Vite build → code generation →
  Bun compile），通过 `import with { type: "file" }` 嵌入前端资源
- 静态资源服务：从 Bun HTML import manifest 切换为自定义
  serveStaticAsset 函数，支持 SPA fallback 和正确的 Cache-Control
- Server 接口：BootstrapOptions 和 StartServerOptions 增加
  staticAssets? 可选参数
- 文档更新：DEVELOPMENT.md 和 README.md 反映新的开发模式，
  主 specs 同步 delta 变更

新增能力：
- static-asset-embedding: 构建时资源扫描与 code generation、
  运行时静态资源服务
- vite-frontend-bundling: Vite 构建配置、code splitting 策略、
  CSS 处理

scripts/build.ts

@@ -1,33 +1,151 @@
-import { rm } from "node:fs/promises";
+import { readdir, rm, writeFile } from "node:fs/promises";
+import { join, relative } from "node:path";
 import { fileURLToPath } from "node:url";
 
-const executablePath = fileURLToPath(new URL("../dist/dial-server", import.meta.url));
-const entrypoint = fileURLToPath(new URL("../src/server/main.ts", import.meta.url));
+const projectRoot = fileURLToPath(new URL("..", import.meta.url));
+const distWebDir = join(projectRoot, "dist/web");
+const buildDir = join(projectRoot, ".build");
+const executablePath = join(projectRoot, "dist/dial-server");
 
-await rm(executablePath, { force: true });
-
-const target = process.env["BUN_TARGET"] ?? process.env["BUILD_TARGET"];
-const result = await Bun.build({
-  compile: target
-    ? {
-        autoloadBunfig: true,
-        autoloadDotenv: true,
-        outfile: executablePath,
-        target: target as Bun.Build.CompileTarget,
-      }
-    : {
-        autoloadBunfig: true,
-        autoloadDotenv: true,
-        outfile: executablePath,
-      },
-  entrypoints: [entrypoint],
-  minify: true,
-  sourcemap: "linked",
-});
-
-if (!result.success) {
-  console.error("构建失败:", result.logs);
-  process.exit(1);
+async function build() {
+  try {
+    await viteBuild();
+    await codeGeneration();
+    await bunCompile();
+    await cleanup();
+    console.log(`Built executable: ${executablePath}`);
+  } catch (error) {
+    await cleanup();
+    console.error("Build failed:", error);
+    process.exit(1);
+  }
 }
 
-console.log(`Built executable: ${executablePath}`);
+async function bunCompile() {
+  console.log("Step 3/3: Bun compile...");
+  await rm(executablePath, { force: true });
+
+  const target = process.env["BUN_TARGET"] ?? process.env["BUILD_TARGET"];
+  const result = await Bun.build({
+    compile: target
+      ? {
+          autoloadBunfig: true,
+          autoloadDotenv: true,
+          outfile: executablePath,
+          target: target as Bun.Build.CompileTarget,
+        }
+      : {
+          autoloadBunfig: true,
+          autoloadDotenv: true,
+          outfile: executablePath,
+        },
+    entrypoints: [join(buildDir, "server-entry.ts")],
+    minify: true,
+    sourcemap: "linked",
+  });
+
+  if (!result.success) {
+    console.error("Bun compile failed:", result.logs);
+    await cleanup();
+    process.exit(1);
+  }
+}
+
+async function cleanup() {
+  await rm(buildDir, { force: true, recursive: true });
+}
+
+async function codeGeneration() {
+  console.log("Step 2/3: Code generation...");
+  await rm(buildDir, { force: true, recursive: true });
+  await Bun.write(join(buildDir, ".gitkeep"), "");
+
+  const allFiles = await scanDir(distWebDir, "/");
+  const importLines: string[] = [];
+  const fileEntries: string[] = [];
+  let indexHtmlVar = "";
+
+  for (let i = 0; i < allFiles.length; i++) {
+    const urlPath = allFiles[i]!;
+    const varName = `f${i}`;
+    const filePath = relative(buildDir, join(distWebDir, urlPath.slice(1)));
+    importLines.push(`import ${varName} from "./${filePath}" with { type: "file" };`);
+
+    if (urlPath === "/index.html") {
+      indexHtmlVar = varName;
+    } else {
+      fileEntries.push(`  "${urlPath}": Bun.file(${varName}),`);
+    }
+  }
+
+  if (!indexHtmlVar) {
+    console.error("index.html not found in dist/web/");
+    process.exit(1);
+  }
+
+  const staticAssetsTs = [
+    `import type { StaticAssets } from "../src/server/static";`,
+    "",
+    ...importLines,
+    "",
+    `export const staticAssets: StaticAssets = {`,
+    `  files: {`,
+    ...fileEntries,
+    `  },`,
+    `  indexHtml: Bun.file(${indexHtmlVar}),`,
+    `};`,
+    "",
+  ].join("\n");
+
+  await writeFile(join(buildDir, "static-assets.ts"), staticAssetsTs);
+
+  const serverEntryTs = [
+    `import { bootstrap } from "../src/server/bootstrap";`,
+    `import { readRuntimeConfig } from "../src/server/config";`,
+    `import { staticAssets } from "./static-assets";`,
+    "",
+    `async function main() {`,
+    `  const { configPath } = readRuntimeConfig();`,
+    `  await bootstrap({ configPath, mode: "production", staticAssets });`,
+    `}`,
+    "",
+    `void main().catch((error) => {`,
+    `  console.error("启动失败:", error instanceof Error ? error.message : error);`,
+    `  process.exit(1);`,
+    `});`,
+    "",
+  ].join("\n");
+
+  await writeFile(join(buildDir, "server-entry.ts"), serverEntryTs);
+}
+
+async function scanDir(dir: string, prefix: string): Promise<string[]> {
+  const entries = await readdir(dir, { withFileTypes: true });
+  const paths: string[] = [];
+  for (const entry of entries) {
+    const fullPath = join(dir, entry.name);
+    const urlPath = `${prefix}${entry.name}`;
+    if (entry.isDirectory()) {
+      paths.push(...(await scanDir(fullPath, `${urlPath}/`)));
+    } else {
+      paths.push(urlPath);
+    }
+  }
+  return paths;
+}
+
+async function viteBuild() {
+  console.log("Step 1/3: Vite build...");
+  const proc = Bun.spawn(["bunx", "--bun", "vite", "build"], {
+    cwd: projectRoot,
+    stderr: "inherit",
+    stdout: "inherit",
+  });
+  const exitCode = await proc.exited;
+  if (exitCode !== 0) {
+    console.error("Vite build failed");
+    process.exit(1);
+  }
+}
+
+await build();

scripts/dev.ts

@@ -0,0 +1,26 @@
+import { fileURLToPath } from "node:url";
+
+const projectRoot = fileURLToPath(new URL("..", import.meta.url));
+
+const apiServer = Bun.spawn(["bun", "--watch", "src/server/dev.ts", ...process.argv.slice(2)], {
+  cwd: projectRoot,
+  stderr: "inherit",
+  stdout: "inherit",
+});
+
+const viteServer = Bun.spawn(["bunx", "--bun", "vite", "--host"], {
+  cwd: projectRoot,
+  stderr: "inherit",
+  stdout: "inherit",
+});
+
+function shutdown() {
+  apiServer.kill();
+  viteServer.kill();
+}
+
+process.on("SIGINT", shutdown);
+process.on("SIGTERM", shutdown);
+
+await Promise.race([apiServer.exited, viteServer.exited]);
+shutdown();