Issue #14, #15 patch

[rcalicdan]

Summary

This PR fixes #14 and #15 by ensuring class-level type aliases are resolved for properties and enhancing error message precision for nested array shapes within Union types.

1. Fix Class-Level Type Alias Resolution for Properties (#14)

• Root Cause: ContractParser::parseProperty() previously only extracted aliases from the property's local @var docblock. It omitted class-level @phpstan-type and @phpstan-import-type declarations from the class hierarchy, causing properties using imported aliases (e.g., list<PluginInfo>) to fail resolution and fall back to class-name checks (must be of type PluginInfo).
• Fix:
  • Updated ContractParser::parseProperty() and parseClassAliases() to pre-load all inherited/imported class-level aliases via parseClassLevelDocs().
  • Updated DocblockExtractor::extractAliases() with !isset() checks to ensure child-class alias definitions take precedence over parent definitions during hierarchy traversal.

2. Preserve Deep Structural Errors in Union Validation (#15)

• Root Cause: When validating a Union type (e.g., array{...} | null), UnionValidator previously discarded inner structural failure messages if all branches failed. It outputted a generic top-level error (must be of type (array{...} | null)), masking the exact failing nested array key or property.
• Fix:
  • Updated UnionValidator to detect and prioritize deep structural errors (e.g., $payload['args'][2] must be... or is missing required key).
  • If an array shape or object branch fails deeply, UnionValidator now surfaces that specific error instead of falling back to the generic union message.

resolve #14, Closes #15