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/store.ts

@@ -25,6 +25,8 @@ export interface SessionError {
 
 export interface State {
   me: User | null;
+  /** Newer release (admins). */
+  update: { version: string; url: string; notes: string } | null;
   connected: boolean;
   sessions: Session[];
   /** Includes subagent sessions loaded on demand. */
@@ -49,6 +51,7 @@ export interface State {
 
 let state: State = {
   me: null,
+  update: null,
   connected: false,
   sessions: [],
   sessionById: {},