fix: mark unused Ollama schema properties as optional

[daniel-lxs]

Description

This PR fixes a Zod validation error that occurs when Ollama returns null for the families field in model details.

Changes

• Made the families field nullable and optional in OllamaModelDetailsSchema
• Marked all unused properties as optional in Ollama schemas to prevent future validation errors
• Only properties that are actually used in the code remain as required fields
• Added comprehensive test cases to verify handling of null values

Properties marked as optional:

OllamaModelDetailsSchema:

• families (nullable and optional)
• format
• parent_model
• quantization_level

OllamaModelSchema:

• digest
• modified_at
• size

OllamaModelInfoResponseSchema:

• modelfile
• parameters
• template

Testing

• Added test case for models with null families field
• Added integration test to verify API response parsing with null values
• All existing tests continue to pass

Related Issues

Fixes #5013

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Important

Fixes Zod validation error by marking unused Ollama schema properties as optional and adding tests for null handling.

• Schema Changes:
  • families field in OllamaModelDetailsSchema is now nullable and optional.
  • Marked unused properties as optional in OllamaModelDetailsSchema, OllamaModelSchema, and OllamaModelInfoResponseSchema.
• Testing:
  • Added test case in ollama.test.ts for models with null families field.
  • Added integration test for API response parsing with null values.
• Behavior:
  • Only required properties are those used in the code, reducing validation errors.

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