Fix Learn site snapshot: use wget --trust-server-names for /ja/ index.html layout

The Build Learn site step failed its `test -f snapshot/ja/index.html`
assertions. The Learn app renders bare links (href="/ja") while vinext runs
with trailingSlash:true, so each bare link 308-redirects to "/ja/". wget named
files after the pre-redirect URL (ja / ja.html with -E), never producing the
directory index.html layout GitHub Pages needs.

--trust-server-names makes wget name files after the redirect target, so
"/ja/" -> ja/index.html and "/ja/rest/" -> ja/rest/index.html. Drops -E and
needs no post-download restructuring. Verified locally: all test -f assertions
pass and converted links resolve under /learn/.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: koriym

.github/workflows/pages.yml

@@ -92,8 +92,17 @@ jobs:
           done
           # Crawl to static HTML. wget exits 8 if any optional asset 404s; that is
           # not fatal for a static snapshot, and steps run under `set -e`.
+          #
+          # The Learn app renders bare links (href="/ja", href="/ja/rest") while the
+          # vinext server runs with trailingSlash:true, so each bare link 308-redirects
+          # to its "/.../" form. By default wget names the local file after the ORIGINAL
+          # (pre-redirect) URL -> "ja"/"ja.html", which never produces the directory
+          # "index.html" layout GitHub Pages needs. --trust-server-names makes wget name
+          # the file after the redirect TARGET ("/ja/" -> ja/index.html, "/ja/rest/" ->
+          # ja/rest/index.html), giving the natural directory structure with no -E and no
+          # post-download restructuring.
           mkdir -p snapshot
-          ( cd snapshot && wget -nv -r -l 3 -p -k -E -nH -e robots=off http://localhost:4399/ ) || true
+          ( cd snapshot && wget -nv -r -l 3 -p -k -nH --trust-server-names -e robots=off http://localhost:4399/ ) || true
           kill "$server_pid" 2>/dev/null || true
           # wget -p does not fetch assets referenced only from inline-style url()
           # (e.g. /bear-logo.png), so copy the public assets in explicitly...