Code blocks should keep the richer Shiki rendering in modern WebUI while avoiding the old WebKit startup crash path by loading Shiki lazily and falling back to Prism only when the runtime cannot safely parse or execute it.
Constraint: Issue #461 is triggered by older Safari/WebKit parsing modern RegExp syntax during startup.
Rejected: Replace Shiki entirely with Prism | visual quality regressed for normal WebUI usage.
Confidence: high
Scope-risk: moderate
Directive: Keep Shiki out of the startup path unless macOS 12 WebView compatibility is re-verified.
Tested: cd desktop && bun run test -- --run src/components/chat/CodeViewer.test.tsx
Tested: cd desktop && bun run lint
Tested: cd desktop && bun run build
Tested: Real WebUI smoke on http://127.0.0.1:1420/ verified six code blocks rendered with data-highlight-engine=shiki.
Not-tested: Physical macOS 12 WebView runtime.
Related: https://github.com/NanmiCoder/cc-haha/issues/461
The desktop app was still falling back to raw text in release builds for some
fenced code blocks, which left bash snippets visually wrong and too heavy for
chat use. This change switches the Shiki path to the JavaScript regex engine,
restores tighter code-block defaults for chat, and bumps the desktop app
version to 0.1.4 for the release artifacts.
Constraint: The packaged Tauri app must render markdown code blocks consistently without relying on WebView WASM behavior
Constraint: Chat code blocks should stay compact and should not show line numbers unless a caller explicitly requests them
Rejected: Keep tuning fallback-only CSS | did not address the packaged highlighter path failing to initialize
Rejected: Leave line numbers on by default | too noisy for assistant replies and bash snippets
Confidence: high
Scope-risk: moderate
Reversibility: clean
Directive: If code blocks regress again, inspect the highlighter engine path before adjusting chat spacing CSS
Tested: cd desktop && bun run lint
Tested: cd desktop && bun run test CodeViewer.test.tsx MarkdownRenderer.test.tsx Sidebar.test.tsx
Tested: cd desktop && bun run build:macos-arm64
Not-tested: Windows packaged build after the engine switch
