Add missing GPA deinit assertions to binary payload tests

[Copilot]

Nine test blocks in src/tests/binary_payload_tests.zig called test_utils.createTestAllocator() but omitted the required defer std.debug.assert(gpa.deinit() == .ok), silently disabling memory leak detection for those tests.

Changes

• src/tests/binary_payload_tests.zig: Added the missing defer std.debug.assert(gpa.deinit() == .ok) immediately after const allocator = gpa.allocator() in all nine affected tests, making them consistent with the full pattern used everywhere else in the test suite:

var gpa = test_utils.createTestAllocator();
const allocator = gpa.allocator();
defer std.debug.assert(gpa.deinit() == .ok);  // was missing in 9 tests

Already addressed (verified in current code)

The other review comments were resolved by the prior commit and are confirmed present:

• classifyBody strips media-type parameters via media_type.baseMediaType() before comparison
• convertRequestBody (v3.0/3.1/3.2 converters) uses mime.selectBestJsonKey() for normalized, deterministic JSON-first selection
• selectConsumesMedia (Swagger v2) uses mime.isJson()/mime.isJsonSuffix() rather than verbatim string comparison
• generateFunctionBodyDirect forces application/json content-type when falling back from form encoding
• Generator emits requestRawWithContentType (not requestRaw) for non-application/json JSON media types (e.g. application/vnd.api+json)
• "type" is present in the isReservedIdent list in both model_generator.zig and api_generator.zig