Infra: split dev and production (releases, services, deploy script)

- Production now runs from ~/freezmo-prod/current (release symlink) as a
  standalone server on :3207; releases are exported by scripts/deploy.sh,
  built and e2e-verified on a temp port, switched atomically, health-
  checked via the new /api/healthz (commit + build time) and rolled back
  automatically on failure. Last 5 releases kept; scripts/rollback.sh for
  manual rollback. Shared env + data live in ~/freezmo-prod/shared/ and
  are symlinked into every release (existing sync/push data migrated and
  verified identical).
- Dev runs from ~/freezmo via freezmo-dev.service: next dev on :3217
  (LAN only), its own build folder (.next-dev via NEXT_DIST_DIR), its own
  data (~/freezmo/.freezmo-dev), DEV badge, dev favicon/theme colour,
  "Freezmo Dev" PWA identity and never the production service worker.
- /api/healthz + the Settings Details version row (short commit + build
  time). output: standalone in next.config (next start still works).
- AGENTS.md documents the workflow rules: only dev updates during a task,
  temporary dirs/ports for test builds, and deploy-at-the-end as the only
  production path. README gains an Environments and deploy section.
- Fix found by the rehearsal: lib/dev-mode.ts must not be a client module
  (a server component importing a constant from a "use client" module
  gets a truthy proxy, which baked dev metadata into production builds).
- SW -> freezmo-v34.

components/SettingsDialog.tsx

@@ -4,6 +4,7 @@ import { AnimatePresence, motion, useDragControls, useReducedMotion } from "fram
 import { useEffect, useRef, useState, useSyncExternalStore } from "react";
 
 import { LOCALES, useI18n, type Locale } from "@/lib/i18n";
+import { useVersion } from "@/lib/use-version";
 import { haptic } from "@/lib/haptics";
 import { modelErrorCopy } from "@/lib/model-errors";
 import { springSheet } from "@/lib/motion";
@@ -53,6 +54,7 @@ export function SettingsDialog({
   const { health, loading, error, refresh, apiKey, checkedAt } = useHealth();
   const installAvailable = useInstallAvailable();
   const { locale, setLocale, t, plural } = useI18n();
+  const version = useVersion();
   const keyInputRef = useRef<HTMLInputElement>(null);
   const settings = useSyncExternalStore(
     settingsStore.subscribe,
@@ -513,6 +515,17 @@ export function SettingsDialog({
                             mono
                             badge={modelBadge(health?.text)}
                           />
+                          {version ? (
+                            <DetailRow
+                              label={t("settings.version")}
+                              value={
+                                version.builtAt
+                                  ? `${version.short} · ${new Date(version.builtAt).toLocaleString()}`
+                                  : version.short
+                              }
+                              mono
+                            />
+                          ) : null}
                         </dl>
                         {health?.mode === "direct-cloud" && health.needsKey ? (
                           <p className="pt-2 text-[11px] leading-relaxed text-[var(--text-subtle)]">
@@ -782,6 +795,12 @@ export function SettingsDialog({
                 ) : null}
 
                 {health ? <HealthPanel health={health} /> : null}
+                {version ? (
+                  <p className="mt-2 text-[11px] text-[var(--text-subtle)]">
+                    {t("settings.version")}: <span className="font-mono">{version.short}</span>
+                    {version.builtAt ? ` · ${new Date(version.builtAt).toLocaleString()}` : ""}
+                  </p>
+                ) : null}
 
                 {/* keeps real content out of the 36px fade strip at the bottom */}
                 <div className="h-9" aria-hidden />