Localize update confirmation and first-run notifications

The update prompt speaks Chinese and points What's new at the
OmarchyCN releases page; the Wi-Fi, update, keybindings, dictation,
and default-agent first-run notices follow.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01QKxGW1raAWaqeU8WdHsMsp

test/shell.d/update-disk-space-test.sh

@@ -129,7 +129,7 @@ pass "disk-space threshold includes the exact boundary"
 
 rm -f "$snapshot_marker" "$gum_marker"
 GUM_STATUS=0 TEST_AVAILABLE_BYTES=$((10 * 1024 * 1024 * 1024)) run_update >/dev/null
-grep -q "confirm Continue with update?" "$gum_marker" ||
+grep -q "confirm 继续更新？" "$gum_marker" ||
   fail "interactive update with enough space uses the normal confirmation prompt"
 [[ -f $snapshot_marker ]] || fail "accepting the normal confirmation starts the update"
 pass "interactive update keeps the normal confirmation prompt when space is sufficient"