chore(upgrade): Add the title template to main ahead of the flavour move

Phase 1 of the Crowdin migration: the flavour copies still override this
for their own builds, so behaviour is unchanged while translations are
gathered against the new source string.

app/src/main/res/values/strings.xml

@@ -209,6 +209,9 @@
 
     <!-- Strings from app-common -->
     <string name="app_name">CAPod</string>
+    <!-- Upgraded app title. %1$s is the app name, %2$s the tier qualifier ("Pro" / "FOSS").
+         Reorder or repunctuate for your language; both placeholders must appear exactly once. -->
+    <string name="app_name_upgraded_template">%1$s %2$s</string>
 
     <string name="general_value_not_available_label">N/A</string>
     <string name="general_error_label">Error</string>