feat: point third-party mode at upstream Yu9191 modules

- subscription URLs now resolve directly to upstream modules (gh-proxy
  mirror / raw), dropping project-owned module and script copies
- remove Resources/ThirdPartyProxyModules and ThirdParty/WlocScripts,
  their pbxproj references, and the contract-test module checks
- third-party save sends lon/lat/acc matching the upstream settings
  script; motion-state simulation is unavailable (upstream lacks it)
- surface the iOS 27 beta 6 gs-loc MITM limitation in the app setup and
  README (zh/en)

ThirdParty/WlocScripts/build.mjs

@@ -1,19 +0,0 @@
-import { build } from "esbuild";
-import { mkdir } from "node:fs/promises";
-
-await mkdir(new URL("./dist/v1/", import.meta.url), { recursive: true });
-
-for (const [entry, outfile] of [
-  ["src/response-entry.js", "dist/v1/wloc.js"],
-  ["src/settings-entry.js", "dist/v1/wloc-settings.js"]
-]) {
-  await build({
-    entryPoints: [entry],
-    outfile,
-    bundle: true,
-    format: "iife",
-    target: ["es2017"],
-    minify: true,
-    legalComments: "eof"
-  });
-}