Update frontend API generation output directory

Changed the output directory for generated frontend APIs to `frontend/src/api` for better organization. Adjusted `.gitignore` accordingly to reflect the new path.

.gitignore

@@ -86,4 +86,4 @@ package-lock.json
 
 
 ### MINE ###
-frontend/src/app/api
+frontend/src/api

build.gradle.kts

@@ -59,7 +59,7 @@ tasks.named("compileJava") {
 tasks.register<GenerateTask>("generateFrontendApi") {
     generatorName.set("typescript-angular")
     inputSpec.set("$projectDir/open_api/api.yml")
-    outputDir.set("$projectDir/frontend/src/app/api")
+    outputDir.set("$projectDir/frontend/src/api")
     configOptions.set(
         mapOf(
             "npmName" to "generated-api",