[BUG]: [swift] getRendererCapabilities drops properties of allOf-composed components in inline catalogs #4227

• I have searched the existing issues to make sure this bug has not already been reported.

Describe the Bug

MessageProcessor.getRendererCapabilities(options:) with includeInlineCatalogs: true and protocol v1.0 emits components whose schema is composed with allOf with only the component property. With BasicCatalog.makeCatalog(version: .v10), Button, CheckBox, ChoicePicker and TextField come out as:

{"properties": {"component": {"const": "Button"}}, "required": ["component"], "type": "object"}

Components whose schema has top-level properties (for example Text, Row, Column) keep their properties.

The cause appears to be buildInlineComponentSchema in swift/core/Sources/A2UICore/Processing/MessageProcessor.swift: it copies only processedSchema["properties"] and processedSchema["required"], so properties and required lists inside allOf members are not merged.

Steps to Reproduce

1. Create a processor: MessageProcessor(catalogs: [BasicCatalog.makeCatalog(version: .v10)], validationConfig: .strict).
2. Call getRendererCapabilities(options: .init(protocolVersion: .v10, includeInlineCatalogs: true)).
3. Inspect ["1.0"]["inlineCatalogs"][0]["components"]["Button"] (same for CheckBox, ChoicePicker, TextField).

Expected Behavior

The inline schema of each component lists the same properties the renderer validates against (for Button: child, action, variant, and so on; for TextField: label, value, and so on).

Screenshots / Video / Logs

Actual output for the four components contains only component, as shown above.

Impact: an agent that builds its prompt from the renderer's inline catalog tells the model these components have no properties. In our measurement a smaller model then omitted required properties such as TextField.label and value. The strict validator still rejects those messages, so this lowers the first-try success rate rather than causing a crash.

Environment Details

• OS: macOS 27.2 (also observed when targeting the iOS 27.2 simulator)
• Browser/Platform: Swift 6.4, Xcode 27.2
• SDK/Package Name & Version: A2UI Swift 0.10.0 (v0.10.0+swift); the same code is on main as of 2026-11-13
• Protocol Version: v1.0
• Agent Framework & LLM Model: not relevant (the output is produced before any model call)

Additional Context

A workaround on the client side is to build the prompt catalog from the original component schemas with allOf and $ref flattened, instead of from getRendererCapabilities.