Add article: OpenUI React renderer progressive rendering

[Aroesler1]

Summary

• Add a source-grounded article for issue Written Content: OpenUI's React Renderer Explained: How Progressive Hydration Works with Streamed Model Output #3 on how OpenUI's React renderer handles streamed model output.
• Focus on current implementation details in @openuidev/react-lang and @openuidev/lang-core: createStreamingParser, autoClose, useOpenUIState, evaluated props, query/mutation deferral, and the last-good render error boundary.
• Clarify that "progressive hydration" here is product language for progressive parsing/rendering, not React SSR hydration.
• Include source references pinned to the current OpenUI commit inspected for the article.

Validation

• npx --yes markdownlint-cli "Articles/OpenUI React Renderer Explained - Progressive Rendering with Streamed Model Output.md" --ignore node_modules
• git diff --check
• Verified claims against OpenUI source at commit e38bfb5652ffdd5b86dd864a8e4de16e00037079

For #3

Transparency: AI-assisted with Codex; reviewed against repository source before submission.

[entelligence-ai-pr-reviews]

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Confidence Score: 5/5 - Safe to Merge

Safe to merge — this PR adds a new article on OpenUI React renderer progressive rendering and introduces no functional code changes that could affect runtime behavior or system correctness. The content-only nature of the change means there are no logic paths, security surfaces, or data flows to evaluate. No review comments were generated during automated analysis, and there are no pre-existing unresolved concerns associated with this PR.

Key Findings:

• The PR is purely additive documentation/article content, meaning there is no executable logic, API surface, or data manipulation introduced that could cause regressions.
• Automated heuristic analysis found zero critical, significant, or medium-severity issues across all scanned files, consistent with a documentation-only change.
• No pre-existing unresolved review comments are associated with this PR, so there is no inherited technical debt to account for before merging.

[Copilot]

Pull request overview

Adds a new technical deep-dive article for issue #3 explaining how OpenUI’s React renderer progressively parses/evaluates streamed OpenUI Lang output and renders incrementally (clarifying this is not React SSR hydration).

Changes:

• Introduces an end-to-end explanation of the streaming pipeline (createStreamingParser → useOpenUIState → Renderer) and the progressive rendering behavior.
• Documents key runtime behaviors: auto-closing incomplete syntax, deferring queries/mutations until streaming ends, and “last good render” error boundary behavior.
• Provides pinned source references to the inspected OpenUI commit for traceability.

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