fix(questionnaire): add additionalProperties false for OpenAI strict mode (#2792)

The gpt-5-mini parser was failing with "additionalProperties is required
to be supplied and to be false" because OpenAI's Responses API enforces
strict structured outputs, which requires additionalProperties: false on
every object schema and every property listed in required.

Also fix the same latent bug in content-extractor's shared schema, which
would break if any of its callers swapped to a strict-mode OpenAI model.

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: Marfuen

apps/api/src/questionnaire/utils/content-extractor.ts

@@ -37,11 +37,13 @@ const questionExtractionSchema = jsonSchema<{
             description: 'The answer/response if provided, null if empty',
           },
         },
-        required: ['question'],
+        required: ['question', 'answer'],
+        additionalProperties: false,
       },
     },
   },
   required: ['questions'],
+  additionalProperties: false,
 });
 
 export interface ContentExtractionLogger {

apps/api/src/questionnaire/utils/question-parser.ts

@@ -135,11 +135,13 @@ export async function parseChunkQuestionsAndAnswers(
                     'The answer to the question. Use null if no answer is provided.',
                 },
               },
-              required: ['question'],
+              required: ['question', 'answer'],
+              additionalProperties: false,
             },
           },
         },
         required: ['questionsAndAnswers'],
+        additionalProperties: false,
       }),
       system: QUESTION_PARSING_SYSTEM_PROMPT,
       prompt: buildParsingPrompt(chunk, chunkIndex, totalChunks),