Fix JSON schema generation for array size predicates

[baweaver]

Fixes #481

Problem

Array size predicates (min_size?, max_size?) were incorrectly generating minLength/maxLength constraints on array items instead of minItems/maxItems on the array itself, violating JSON Schema specification.

Root Cause

The JSON schema compiler applied all predicates to array items when the target type was an array, without distinguishing between array-level constraints (size of array) and item-level constraints (properties of individual items).

Solution

• Enhanced predicate processing to detect array size predicates (min_size?, max_size?)
• Added context awareness using the member flag to distinguish array-level vs item-level predicates
• Array size predicates now correctly map to minItems/maxItems when not in item context
• Item-level predicates continue to map to minLength/maxLength as expected

Changes

• lib/dry/schema/extensions/json_schema/schema_compiler.rb: Enhanced predicate processing logic
• spec/integration/extensions/json_schema/array_size_predicates_spec.rb: Comprehensive test coverage
• CHANGELOG.md: Document the fix

Before/After

# Before: Incorrect JSON schema
required(:users).value(:array?, min_size?: 5).each(:str?)
# => {type: "array", items: {type: "string", minLength: 5}}

# After: Correct JSON schema  
required(:users).value(:array?, min_size?: 5).each(:str?)
# => {type: "array", minItems: 5, items: {type: "string"}}