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/styles.css

@@ -3054,3 +3054,35 @@ button.danger-solid {
   word-break: break-all;
   font-size: 12px;
 }
+
+.cli-steps {
+  margin: 0 0 10px;
+  padding-left: 20px;
+  display: flex;
+  flex-direction: column;
+  gap: 10px;
+}
+
+.memory-card .icon {
+  color: var(--purple);
+}
+
+.update-chip {
+  display: flex;
+  align-items: center;
+  gap: 6px;
+  margin: 0 12px 8px;
+  padding: 6px 10px;
+  border-radius: 8px;
+  background: color-mix(in srgb, var(--accent) 18%, var(--bg1));
+  color: var(--fg0);
+  font-size: 13px;
+  text-decoration: none;
+}
+.whatsnew {
+  margin: 10px 0 16px;
+  padding-left: 20px;
+  display: flex;
+  flex-direction: column;
+  gap: 6px;
+}