Feat/runtime response validation

[Code-Paragon]

Description

Implements a lightweight, zero-dependency runtime response validation system to safely parse unknown API payloads and prevent invalid data from propagating through the SDK.

• Created composable schema builders (string, number, boolean, null, literal, optional, array, object, union).
• Implemented strongly typed parsing returning discriminated ValidationResult<T> objects.
• Added structured path tracking (e.g., data.members[2].id) for descriptive validation failures.
• Enforced strict depth limitation (max depth 20) to prevent recursive payload attacks or stack overflows.
• Backed by 93 comprehensive unit tests covering primitives, nested objects, arrays, unions, and malformed responses.

Closes #467 (or respective issue number if applicable).

Type of Change

• Bug fix (fix(scope): message)
• New feature (feat(scope): message)
• Documentation (docs(scope): message)
• Refactoring (refactor(scope): message)
• CI/CD (ci(scope): message)
• Other

PR Title Format

This PR follows Conventional Commits:

Testing

• Tests pass locally
• New tests added (if applicable)

Checklist

• PR title follows type(scope): message format
• Code follows project style guidelines
• Self-review completed

[Lakes41]

This PR cannot be merged automatically because it has merge conflicts.

Please update the branch with the latest base branch and resolve the conflicts.

After the conflicts are resolved and checks pass, the automation can review it again.