chore: update .gitignore files to include app.json and manifest.json

- Added app.json to the main .gitignore to prevent tracking of configuration files.
- Included manifest.json in the api/.gitignore to exclude it from version control.

Author: shobhitupadhyayy

.gitignore

@@ -16,6 +16,9 @@
 # Mono auto generated files
 mono_crash.*
 
+# App JSON file
+app.json
+
 # Build results
 [Dd]ebug/
 [Dd]ebugPublic/

api/.gitignore

@@ -366,4 +366,5 @@ database/
 /cmsMigrationData
 /migration-data
 **/copy*
-**copy.ts
+**copy.ts
+manifest.json