overlay: rebase on appstore package 1.4.8 (candidate for 2026-11-08 window)

- Dockerfile FROM: appstore 1.4.5 image (202610230221180000) -> 1.4.8
  (202611030321030000). Same LibreChat upstream 0.8.8 in both - the package
  delta is tooling only: uv 0.13.5->0.13.7 and Node.js 22.23.4 (security fix,
  1.4.7), base image 6.0.1 (eMudhra cert fix, 1.4.4 - already in 1.4.5).
- All overlay anchors verified against the real 1.4.8 image dist (title tag,
  manifest link crossorigin, viewport meta, theme-color #171717, webmanifest
  name/colors, 'MCP Servers' + 'Every AI for Everyone.' strings, index.*.js,
  sw.js): unchanged, no porting needed.
- release.sh BASE_IMAGE default follows the pin.

CloudronManifest.json

@@ -1,6 +1,6 @@
 {
   "id": "ai.librechat.cloudronapp",
-  "version": "1.4.5",
+  "version": "1.4.8",
   "title": "LibreChat",
   "upstreamVersion": "0.8.8",
   "author": "Danny Avila",
@@ -56,4 +56,4 @@
   ],
   "icon": "file://logo.png",
   "dockerImage": "registry.inference.coop/co-op/librechat-custom:20261031-2a98892"
-}
+}