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.

docker-compose.yml

@@ -1,11 +1,17 @@
 services:
   ihasmail:
     build: .
-    image: ihasmail:latest
-    env_file: .env
+    image: ihasmail:2
     restart: unless-stopped
-    networks: [edge]
     ports:
-      - "127.0.0.1:8080:8000"
-networks:
-  edge: {}
+      - "8080:8080"
+    environment:
+      STALWART_URL: ${STALWART_URL:-https://mail.example.com}
+      APP_SECRET: ${APP_SECRET:?set APP_SECRET in .env (openssl rand -base64 48)}
+      APP_NAME: ${APP_NAME:-ihasmail}
+      TRUST_PROXY: "1"
+      IMAGE_PROXY: "1"
+    volumes:
+      - ihasmail-data:/data
+volumes:
+  ihasmail-data: