Fix unbound APP_KEYS variable in install_wolf()'s app injector

install_wolf()'s own copy of the app-injection step used $APP_KEYS instead
of its actual variable $_APP_KEYS (the underscore-prefixed name is
install_wolf()'s own; APP_KEYS is manage.sh's separate copy's variable).
Confirmed live: under 'set -u' without 'set -e' this was a non-fatal
"APP_KEYS: unbound variable" error printed mid-install right after "Wolf
restarted with updated config" — the script kept going, but the
Steam-storage-location success message never printed.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VLX1yYKJExGSXmgUhxKQG6

services/wolf.sh

@@ -3377,7 +3377,13 @@ PYEOF
         # Nothing else to do for Steam storage: Wolf's state folder lives on the
         # game drive, so Steam installs, games, and Proton prefixes land there
         # automatically the first time you connect. No fix-perms, no symlinks.
-        if echo "$APP_KEYS" | grep -qw steam; then
+        # _APP_KEYS, not APP_KEYS — this install-time copy uses the
+        # underscore-prefixed name (set earlier in install_wolf()); APP_KEYS
+        # is manage.sh's own copy's variable name. Confirmed live: this was
+        # a silent no-op under 'set -u' without 'set -e' (bash prints
+        # "APP_KEYS: unbound variable" and just continues), so the Steam
+        # storage-location message never printed but nothing else broke.
+        if echo "$_APP_KEYS" | grep -qw steam; then
             log_success "Steam will install games to $WOLF_STATE_DIR (on the game drive)"
         fi
     else