Add support for an additional exclusion file besides .gitignore and .geminiignore (#16487)

Co-authored-by: Adam Weidman <adamfweidman@google.com>

packages/core/src/utils/memoryDiscovery.test.ts

@@ -436,6 +436,7 @@ Subdir memory
       {
         respectGitIgnore: true,
         respectGeminiIgnore: true,
+        customIgnoreFilePaths: [],
       },
       200, // maxDirs parameter
     );
@@ -472,6 +473,7 @@ My code memory
       {
         respectGitIgnore: true,
         respectGeminiIgnore: true,
+        customIgnoreFilePaths: [],
       },
       1, // maxDirs
     );