GraphQL schema fails to initialize when stored procedure parameter defaults use non-numeric strings Description:

[JerryNixon]

When a stored procedure entity defines parameter defaults using non-numeric strings (for example "default": "number"), Data API builder fails to start with GraphQL enabled. The service throws a DataApiBuilderException during schema generation and /graphql becomes unavailable.

Steps to Reproduce:

1. Define a stored procedure entity like this:

   "GetSeriesActors": {
     "source": {
       "object": "dbo.GetSeriesActors",
       "type": "stored-procedure",
       "parameters": [
         { "name": "seriesId", "required": false, "default": "number" },
         { "name": "top", "required": false, "default": "number" }
       ]
     },
     "graphql": { "enabled": true, "operation": "mutation" }
   }
   

2. Start DAB with GraphQL enabled.

3. Observe logs.

Expected Behavior: DAB should either:

• Treat "default": "number" as a literal string value, or
• Reject invalid defaults during configuration validation with a clear error message before startup.

Actual Behavior: DAB starts but fails when GraphQL initializes. The logs show:

DataApiBuilderException: The parameter value number provided in configuration cannot be converted to the type Int
System.FormatException: The input string 'number' was not in a correct format.
   at System.Int32.Parse(String s)

After this error, /graphql is unavailable, though REST endpoints continue to function normally.

Environment:

• Data API builder version: 1.7.75
• Database: SQL Server
• Host: Azure Container Apps
• Authentication: StaticWebApps

Notes: The exception originates from GraphQLStoredProcedureBuilder.ConvertValueToGraphQLType when attempting to parse the invalid default value. DAB should validate or sanitize stored procedure parameter defaults before GraphQL schema generation to prevent this runtime failure.