Fix Gradle cache save races when restore hits a fallback key.

Save always uses the job scope key; do not reuse cache-primary-key from a partial restore (e.g. Android saving build-jar).

Co-authored-by: Cursor <cursoragent@cursor.com>

.github/actions/cache-gradle-build/action.yml

@@ -10,9 +10,9 @@ outputs:
   cache-hit:
     description: Whether an exact cache key match was restored
     value: ${{ steps.cache.outputs.cache-hit }}
-  cache-primary-key:
-    description: Primary cache key to pass to the save action after the build
-    value: ${{ steps.cache.outputs.cache-primary-key }}
+  cache-save-scope:
+    description: Scope to pass to the save action (always this job's scope, not a restored fallback key)
+    value: ${{ inputs.scope }}
 
 runs:
   using: composite