refactor(web_core): extract shared Zod schema introspection and metadata utilities

[josemontespg]

Overview

Several areas within @a2ui/web_core inspect and traverse Zod schemas to classify properties for reactive binding and child lifecycle management:

1. GenericBinder / scrapeSchemaBehavior (renderers/web_core/src/v0_9/rendering/generic-binder.ts): inspects schemas to build a behavior tree (DYNAMIC, ACTION, STRUCTURAL, CHECKABLE, STATIC).
2. NodeResolver / extractRefFields (renderers/web_core/src/v0_9/nodes/ref-fields.ts): inspects schemas to classify child component references (single, list, nested).

Currently, both modules independently access private Zod _def internals (typeName, innerType, description, options, shape()) and implement separate unwrapping loops for ZodOptional, ZodNullable, ZodDefault, and ZodEffects.

Goals & Motivation

• Centralize Zod Introspection: Consolidate schema unwrapping and property reflection into a dedicated utility module (e.g. renderers/web_core/src/v0_9/schema/schema-reflection.ts).
• Eliminate Raw _def Leaks: Provide clean helper functions (unwrapSchema, getSchemaDescriptions, isZodUnion, isZodObject) so binders and resolvers do not couple to Zod internals.
• Extend Schema Metadata Stamping: Broaden the a2uiChildRef metadata pattern introduced in PR feat(react): render A2uiSurface through the node layer #2393 (markChildRef / childRefKindOf) to cover Action and Dynamic* schemas (a2uiKind: 'action' | 'dynamic' | 'child-list' | 'component-id'). This completely eliminates fragile string parsing of description pointers (REF:common_types.json#/$defs/...) when inspecting schemas.

Proposed Changes

1. New Utility Module (schema-reflection.ts):
   • unwrapSchema(schema: z.ZodTypeAny): Recursively unwraps wrappers while aggregating metadata and descriptions.
   • getSchemaKind(schema: z.ZodTypeAny): Resolves stamped A2UI schema kinds.
2. Refactor Call Sites:
   • Refactor ref-fields.ts to use unwrapSchema.
   • Refactor generic-binder.ts to use unwrapSchema and the shared reflection helpers.
3. Metadata Enrichment (common-types.ts):
   • Add markSchemaKind to ActionSchema, DynamicValueSchema, DataBindingSchema.

References

• Discussion on PR feat(web_core): enhance generic binder schema inference #2359: feat(web_core): enhance generic binder schema inference #2359 (comment)
• PR feat(react): render A2uiSurface through the node layer #2393: Node layer schema metadata implementation (commit 3a2f5f24)

[josemontespg]

Closing: created prematurely by agent, apologies!