Modernize generation pipeline and Remix integration

[leoafarias]

Summary

• Streamline the AI deck generation pipeline, including planning, validation, repair, result application, cancellation, and error-state handling.
• Update SuperDeck to Mix 2.2.0-beta.0 and Remix 1.0.0-beta.1, migrate affected styling APIs, and pin the compatible Hero UI migration revision.
• Add bounded slide-capture concurrency with regression coverage for permit ordering and over-release protection.
• Simplify the Playground UI by removing unused component adapters, duplicate prompt data, and stale live-generation artifacts.
• Refresh dependency locks, tests, lint baselines, and generated-source compatibility across the workspace.

Why

The published Hero UI release targets the legacy Remix API, while the latest Remix beta requires updated component contracts. The generation workflow also needed clearer terminal states and less duplicated or unused code, and concurrent slide capture needed an explicit upper bound.

Validation

• fvm dart run melos run build_runner:build --no-select
• fvm dart run melos run analyze:all
• fvm dart run melos run test --no-select
• Real-browser Mermaid integration tests: 2 passed
• Demo macOS integration suite: 39 passed
• Playground macOS debug build
• Demo web debug build and WASM compatibility dry run
• Formatting, generated-drift, legacy-API, whitespace, and credential-pattern audits

[github-actions]

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