fix: support typed Go slices and maps in validation

[Yanhu007]

Fixes #238

Problem

The validator only accepts []any for JSON arrays and map[string]any for JSON objects. Typed Go slices like []string or []map[string]interface{} are rejected with:

invalid jsonType []string

Even though these types serialize correctly to JSON and match the schema.

Fix

Use reflect as a fallback in typeOf() to detect:

• Slices/arrays → treated as JSON arrays
• Maps with string keys → treated as JSON objects

When validation needs to iterate over these values (in arrValidate/objValidate and unevalFrom), the typed collections are converted to []any / map[string]any first.

Testing

All existing tests pass. Manually verified:

schema.Validate([]string{"hello", "world"})          // ✅ was: invalid jsonType
schema.Validate([]map[string]string{{"key": "val"}}) // ✅ was: invalid jsonType