feat(fullstack): Add application form status, add submissions of forms, update DB schema

legalconsenthub-backend/src/main/kotlin/com/betriebsratkanzlei/legalconsenthub/error/ApplicationFormInvalidStateException.kt

@@ -0,0 +1,11 @@
+package com.betriebsratkanzlei.legalconsenthub.error
+
+import com.betriebsratkanzlei.legalconsenthub_api.model.ApplicationFormStatus
+import java.util.UUID
+
+class ApplicationFormInvalidStateException(
+    val applicationFormId: UUID,
+    val currentState: ApplicationFormStatus,
+    val expectedState: ApplicationFormStatus,
+    val operation: String
+) : RuntimeException("Cannot $operation application form with ID $applicationFormId. Current state: $currentState, expected state: $expectedState") 

legalconsenthub-backend/src/main/kotlin/com/betriebsratkanzlei/legalconsenthub/error/ExceptionHandler.kt

@@ -31,6 +31,22 @@ class ExceptionHandler {
             )
     }
 
+    @ResponseBody
+    @ExceptionHandler(ApplicationFormInvalidStateException::class)
+    @ResponseStatus(HttpStatus.BAD_REQUEST)
+    fun handleInvalidStateError(e: ApplicationFormInvalidStateException): ResponseEntity<ProblemDetails> {
+        logger.warn(e.message, e)
+        return ResponseEntity.status(HttpStatus.BAD_REQUEST).contentType(MediaType.APPLICATION_PROBLEM_JSON)
+            .body(
+                ProblemDetails(
+                    title = "Invalid State",
+                    status = HttpStatus.BAD_REQUEST.value(),
+                    type = URI.create("about:blank"),
+                    detail = e.message ?: "Operation not allowed in current state"
+                )
+            )
+    }
+
     @ResponseBody
     @ExceptionHandler(
         ApplicationFormNotCreatedException::class,