chore: add deno task server helper (build + run with --browser)

- add scripts/server.ts that builds mailbrus-server (debug) and starts
  it with --browser, cleaning up on SIGINT/SIGTERM
- wire it as `deno task server` in deno.json

Author: antono

deno.json

@@ -5,6 +5,7 @@
     "dev": "vite dev",
     "build": "vite build",
     "preview": "vite preview",
+    "server": "deno run --allow-read --allow-write --allow-run --allow-env --allow-net scripts/server.ts",
     "e2e:generate": "deno run -A e2e/fixtures/generate.ts",
     "test:e2e": "node_modules/.bin/playwright test --config=e2e/playwright.config.ts --project=chromium",
     "e2e:ui": "node_modules/.bin/playwright test --config=e2e/playwright.config.ts --ui",

scripts/server.ts

@@ -0,0 +1,58 @@
+#!/usr/bin/env -S deno run --allow-read --allow-write --allow-run --allow-env --allow-net
+/**
+ * Build and start mailbrus-server with --browser for local development.
+ *
+ *   deno task server
+ *
+ * Builds the server binary (debug), starts it with --browser, and opens
+ * the default web browser. Ctrl-C stops the server cleanly.
+ */
+
+const ROOT = new URL("..", import.meta.url).pathname.replace(/\/$/, "");
+const SERVER_BIN = `${ROOT}/target/debug/mailbrus-server`;
+
+function log(msg: string) {
+  console.log(`[server] ${msg}`);
+}
+
+async function build(): Promise<boolean> {
+  log("building mailbrus-server (debug)…");
+  const { success } = await new Deno.Command("cargo", {
+    args: ["build", "-p", "mailbrus-server"],
+    cwd: ROOT,
+    stdout: "inherit",
+    stderr: "inherit",
+  }).output();
+  return success;
+}
+
+function start(proc: Deno.ChildProcess) {
+  proc.status.then((s) => {
+    log(`server exited with code ${s.code}`);
+    Deno.exit(s.code ?? 1);
+  }).catch(() => {});
+}
+
+if (!await build()) {
+  log("build failed");
+  Deno.exit(1);
+}
+
+log("starting server with --browser");
+const child = new Deno.Command(SERVER_BIN, {
+  args: ["--browser"],
+  cwd: ROOT,
+  stdout: "inherit",
+  stderr: "inherit",
+}).spawn();
+
+start(child);
+
+const stop = () => {
+  log("shutting down…");
+  try { child.kill("SIGTERM"); } catch { /* already gone */ }
+};
+Deno.addSignalListener("SIGINT", stop);
+Deno.addSignalListener("SIGTERM", stop);
+
+await child.status;