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.

web/src/views/compose/ComposerDock.tsx

@@ -0,0 +1,19 @@
+import { useCompose } from "@/store/compose";
+import { Composer } from "./Composer";
+import { useIsMobile } from "@/ui/misc";
+
+export function ComposerDock() {
+  const drafts = useCompose((s) => s.drafts);
+  const activeKey = useCompose((s) => s.activeKey);
+  const isMobile = useIsMobile();
+  if (!drafts.length) return null;
+  // On mobile only the active composer is shown (full screen); others are minimized bars.
+  const visible = isMobile ? drafts.filter((d) => d.key === activeKey || d.minimized) : drafts;
+  return (
+    <div className="composer-dock">
+      {visible.map((d) => (
+        <Composer key={d.key} draft={isMobile && d.key !== activeKey ? { ...d, minimized: true } : d} />
+      ))}
+    </div>
+  );
+}