ihasmail 2.0: rebuild as Stalwart-first JMAP webmail

Replace the FastAPI/HTMX prototype with a Node/Hono session proxy and a
React 19/Vite SPA. Mail (conversation view, search operators, labels,
sanitised HTML, privacy image proxy, invites, undo send, templates),
calendar (month/week/day/agenda, invites, free/busy, categories,
context menus), contacts (JSContact, groups, vCard), files, Sieve filter
builder (incl. filter-from-message with retroactive apply), vacation,
identities with default + Reply-To, PWA/mobile layout, push via SSE,
in-memory mock Stalwart for dev, Docker + CI.

server/src/index.ts

@@ -0,0 +1,27 @@
+import { serve } from "@hono/node-server";
+import { config } from "./config.js";
+import { createApp, sessions } from "./app.js";
+
+async function main() {
+  await sessions.init();
+  const app = createApp();
+  const server = serve({ fetch: app.fetch, hostname: config.host, port: config.port }, (info) => {
+    console.log(`[ihasmail] ${config.appName} listening on http://${info.address}:${info.port}`);
+    console.log(`[ihasmail] upstream Stalwart: ${config.stalwartUrl}`);
+    console.log(`[ihasmail] static dir: ${config.staticDir}`);
+  });
+
+  const shutdown = async (signal: string) => {
+    console.log(`[ihasmail] ${signal} received, shutting down`);
+    server.close();
+    await sessions.close();
+    process.exit(0);
+  };
+  process.on("SIGINT", () => void shutdown("SIGINT"));
+  process.on("SIGTERM", () => void shutdown("SIGTERM"));
+}
+
+main().catch((err) => {
+  console.error("[ihasmail] fatal:", err);
+  process.exit(1);
+});