chore(fastlane): support p8 key path

apps/ios/fastlane/.env.example

@@ -1,6 +1,11 @@
 # App Store Connect API key (pick one approach)
 #
-# Recommended:
+# Recommended (use the downloaded .p8 directly):
+# ASC_KEY_ID=XXXXXXXXXX
+# ASC_ISSUER_ID=xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
+# ASC_KEY_PATH=/absolute/path/to/AuthKey_XXXXXXXXXX.p8
+#
+# Or (JSON key file):
 # APP_STORE_CONNECT_API_KEY_PATH=/absolute/path/to/AuthKey_XXXXXX.json
 #
 # Or: