fix(ui): render injected XML blocks and PR refs like the rest of the app in thread UI

[adboio]

Problem

The canvas Thread side panel (ThreadPanel) rendered user prompts as plain whitespace-pre-wrap text, so the injected context blocks (<user_custom_instructions>, <canvas_generation_instructions>, <channel_context>) and inline mention chips (<github_pr/>, <file/>, …) leaked as raw XML tags instead of getting their custom rendering. PR URLs in agent prose also rendered as plain anchors rather than the GithubRefChip the conversation view uses — the thread UI was out of step with the rest of the app.

Changes

• ChatMarkdown: render GitHub issue/PR URLs as GithubRefChip (mirrors MarkdownRenderer), so PR refs in agent prose get their chip rendering in both the main ChatThread and the canvas ThreadPanel.
• Shared usePromptDisplayContent hook: extracts the channel_context → canvas_generation_instructions → user_custom_instructions stripping chain that was copy-pasted in both UserMessage and UserBubble; both now consume the hook (no behavior change — covered by existing tests).
• ThreadPanel.UserPromptRow: uses the hook to strip the injected blocks (always-on; the panel has no split-tab tags so the flag arg is false) and parses mention chips via parseFileMentions, falling back to ChatMarkdown — matching how UserMessage/UserBubble render prompts.

How did you test this?

• ChatMarkdown.test.tsx — new: GitHub PR URL → GithubRefChip, non-GitHub links stay plain anchors.
• ThreadPanel.test.tsx — new: injected custom-instructions + channel-context XML is stripped (not rendered raw); injected <github_pr/> chip renders as a chip.
• usePromptDisplayContent.test.ts — new: covers all three block types, flag-gating of tags, and always-on stripping.
• Existing UserMessage.test.tsx (5), channelContext/customInstructions/canvasInstructions (10), and full chat-thread + session-update + ThreadPanel suites (84 tests, 14 files) pass. tsc --noEmit and biome check clean.

Automatic notifications

• Publish to changelog?
• Alert Sales and Marketing teams?

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Created with PostHog Code

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[github-actions]

React Doctor found 1 issue in 1 file · 1 warning.

1 warning

src/features/sessions/components/chat-thread/ChatMarkdown.tsx

• ⚠️ src/features/sessions/components/chat-thread/ChatMarkdown.tsx:74 Children type checked at runtime no-polymorphic-children

_{Reviewed by React Doctor for commit 89ae939.}