Theseus 0.3.77: translator provider setting, Pithos 0.3.13, CF-blocked error pages

- Settings → Language gets a Translator engine radio: pick between
  LibreTranslate (hosted — current default) and Bergamot (on-device —
  WASM engine, bundled in a later release; falls back to LibreTranslate
  for now with a one-time notice). See bergamot.x for the plan.
- Bundles Pithos 0.3.13: menu reflows in setup order with the account on
  top, files waiting to upload are shown and go up on their own, s3d
  one-shot commands never open the database at once.
- Error page handles Cloudflare Bot Fight 503s: branded page explains the
  Electron TLS fingerprint and offers a one-click retry to a .bch mirror
  when one is published (path preserved).
- Fixes did-fail-load suppression: a cert error during the HTTPS fallback
  now surfaces the branded error page instead of being swallowed.

package.json

@@ -1,6 +1,6 @@
 {
   "name": "theseus-navigator",
-  "version": "0.3.76",
+  "version": "0.3.77",
   "license": "MPL-2.0",
   "description": "Theseus Navigator — a browser that follows the thread. By Silent Mode, a Deviant project.",
   "author": "Silent Mode",