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/components/Settings.tsx

@@ -5,6 +5,7 @@ import { useFetch, useModels } from "../hooks";
 import { getLang, languages, setLang, useT, type Key } from "../i18n";
 import { navigate } from "../router";
 import { useStore } from "../store";
+import { canPrompt, isInstalled, onInstallChange, platformHint, promptInstall } from "../install";
 import { currentSubscription, disablePush, enablePush, pushSupported, testPush } from "../push";
 import { applyTheme, getTheme, getThemeMode, onThemeChange, THEME_MODES, THEMES, type Theme, type ThemeMode } from "../theme";
 import { setReasoningMode, useReasoningMode, type ReasoningMode } from "../prefs";
@@ -109,12 +110,36 @@ function InterfaceSettings() {
         <div className="hint">{t("settings.reasoningHint")}</div>
         <label>{t("settings.notifications")}</label>
         <PushControl />
+        <label>{t("install.label")}</label>
+        <InstallControl />
+        <label>{t("settings.version")}</label>
+        <VersionInfo />
         <div className="hint">{t("settings.notificationsHint")}</div>
       </div>
     </div>
   );
 }
 
+function InstallControl() {
+  const t = useT();
+  const prompt = useSyncExternalStore(onInstallChange, canPrompt);
+  if (isInstalled()) return <span className="chip">{t("install.installed")}</span>;
+  if (prompt)
+    return (
+      <div>
+        <button className="small primary" onClick={() => void promptInstall()}>
+          <Icon name="download" /> {t("install.button")}
+        </button>
+      </div>
+    );
+  return <div className="hint">{t(`install.hint.${platformHint()}` as Key)}</div>;
+}
+
+function VersionInfo() {
+  const info = useFetch<{ version: string; commit?: string }>("/info").data;
+  return <div className="hint mono">{info ? `CodeCraft ${info.version}${info.commit ? ` (${info.commit})` : ""}` : "…"}</div>;
+}
+
 /** Web Push on this device: enable/disable and a test notification. */
 function PushControl() {
   const t = useT();
@@ -313,6 +338,7 @@ interface ModelRow {
   cache_read_price?: number;
   cache_write_price?: number;
   max_concurrency?: number;
+  fallback?: string;
   options?: Record<string, unknown>;
 }
 
@@ -479,6 +505,7 @@ function ProviderEditor({ name, p, reload }: { name: string; p: Json; reload: ()
                   <th>{t("settings.priceCacheRead")}</th>
                   <th>{t("settings.priceCacheWrite")}</th>
                   <th title={t("settings.maxConcurrencyHint")}>{t("settings.slots")}</th>
+                  <th title={t("settings.fallbackHint")}>{t("settings.fallback")}</th>
                   <th />
                 </tr>
               </thead>
@@ -516,6 +543,9 @@ function ProviderEditor({ name, p, reload }: { name: string; p: Json; reload: ()
                     <td>
                       <input type="number" min={1} value={m.max_concurrency ?? ""} placeholder="∞" onChange={(e) => setModel(i, { max_concurrency: num(e.target.value) })} />
                     </td>
+                    <td>
+                      <ModelSelect value={m.fallback ?? ""} onChange={(v) => setModel(i, { fallback: v || undefined })} emptyLabel="–" />
+                    </td>
                     <td>
                       <button className="small ghost danger" onClick={() => setModels(models.filter((_, j) => j !== i))} aria-label={t("common.remove")}>
                         <Icon name="close" />