Add terminal client, memory, model fallback, version and install improvements

- codecraft: full-screen terminal client (ratatui) – local tools and files,
  models via the CodeCraft server gateway or own providers (standalone with a
  guided setup), slash commands, @files, permission dialogs, resume, update
- Static Linux CLI builds (x86_64/aarch64, cargo-zigbuild) served by the
  server: /cli/install.sh and /cli/download/<target>
- Project memory (remember tool, .codecraft/memory.md) and personal memory
- Model fallback when a host is unreachable or a budget is used up
- Version/commit in UI and health, daily release check, "What's new" dialog
- PWA: install button, maskable icon, manifest id and screenshots
- Case-insensitive detection of connection errors for retries

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

web/src/whatsnew.ts

@@ -0,0 +1,19 @@
+/** "What's new" entries per version (shown once after an update). */
+export const WHATS_NEW: Record<string, { en: string[]; de: string[] }> = {
+  "0.1.0": {
+    en: [
+      "Terminal client `codecraft`: work locally like with Claude Code – Settings → Account → Terminal client",
+      "Automations: agents on a schedule (ask an agent in any chat to set one up)",
+      "Review loops per mode, project memory and personal memory",
+      "Web terminal, git worktrees, accept changes hunk by hunk, voice input",
+      "15 colour themes with light/dark/auto, push notifications on your phone",
+    ],
+    de: [
+      "Terminal-Client `codecraft`: lokal arbeiten wie mit Claude Code – Einstellungen → Konto → Terminal-Client",
+      "Automationen: Agenten nach Zeitplan (lass sie dir in einem Chat von einem Agenten einrichten)",
+      "Review-Schleifen pro Modus, Projekt-Gedächtnis und persönliches Gedächtnis",
+      "Web-Terminal, Git-Worktrees, Änderungen stückweise übernehmen, Spracheingabe",
+      "15 Farbthemes mit Hell/Dunkel/Auto, Push-Benachrichtigungen aufs Handy",
+    ],
+  },
+};