Update CI tooling and clarify Gbéewá capabilities

[eosobande]

Summary

• Update GitHub Actions to Node.js 24-compatible action versions.
• Upgrade Gradle from 8.11.1 to 8.13.
• Upgrade the Vanniktech publishing plugin from 0.34.0 to 0.35.0.
• Use publishAndReleaseToMavenCentral so the release job waits for deployment validation.
• Document typed, omni-directional result delivery.
• Add a result-delivery diagram.
• Clarify mounted sibling delivery and one-consumer behavior.
• Document ViewModel hoisting and retain { ResultStore() } as configuration-change options.

Why

GitHub now warns about actions that use the deprecated Node.js 20 runtime.

The previous Maven Central plugin uploaded an automatic deployment without waiting for its final status. Version 0.35.0 waits until the deployment reaches PUBLISHED or FAILED.

The README also did not clearly surface several supported delivery patterns or the composition-owned retention option.

Impact

This change does not modify the Gbéewá runtime API.

Release builds now use the updated Gradle and Maven publishing tools. The publication job reports success only after Maven Central reaches a terminal deployment state.

The retain example is optional. It requires Compose Runtime 1.10.0 or later and androidx.compose.runtime:runtime-retain.

Neither retain nor ViewModel restores pending results after process death.

Validation

• ./gradlew clean check apiCheck koverVerify --stacktrace
• ./gradlew :gbeewa:publishAndReleaseToMavenCentral --dry-run -PVERSION_NAME=0.1.1
• Parsed both workflow YAML files.
• Ran git diff --check.

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