feat(canvas): per-channel CONTEXT.md replacing Settings entry

[raquelmsmith]

video desc

https://www.loom.com/share/84096ec91e3143dca32d70390bffc2ec

Summary

• Replaces the placeholder Settings entry under each channel in the canvas sidebar with a CONTEXT.md entry that opens a versioned, deep-linkable markdown editor.
• Wires the desktop folder-instructions endpoints from feat(file-system): add versioned instructions for desktop folders posthog#61494 into a new useFolderInstructions hook + WebsiteContext view: rendered/edit toggle, save publishes a new version with optimistic concurrency, version dropdown surfaces history.
• Refetches latest on every mount so the view reflects edits made by other users or agents.

Notes

• Backend depends on feat(file-system): add versioned instructions for desktop folders posthog#61494 being merged before this is useful end-to-end. Without it the editor shows the empty state and saves will 404.
• Past version content is not currently fetched (backend exposes content only on the latest endpoint today) — selecting an older version shows its metadata and a callout.
• This is the same feature originally drafted in PR feat(sidebar): feature-flagged file-system tree sidebar #2468 (commit 033b79f), re-applied against current main after the canvas refactor.

Test plan

• Open a channel, click CONTEXT.md — empty state renders with channel name.
• Create + save: new version appears; rendered mode shows markdown.
• Edit + save again: version dropdown lists both versions; "Latest" selection works.
• Open same channel from a second client; remote edit appears on mount (no refresh).
• Old per-channel /settings URL no longer resolves; route gone from generated tree.

🤖 Generated with Claude Code

[greptile-apps]

Comments Outside Diff (1)

1. packages/ui/src/features/canvas/components/WebsiteContext.tsx, line 450-458 (link)

   Conflict callout has no action

   The message says "Reload to merge your changes" but there is no button to perform that reload. The user is left in edit mode with their draft and a stale baseVersion, unable to proceed except by clicking "Discard" and manually re-entering their changes. Consider adding a "Reload" button that calls queryClient.invalidateQueries on the instructions key and re-seeds the draft — or at minimum change the message to "Discard your changes and reload to see the latest version" to match the only available action.

   Prompt To Fix With AI

   This is a comment left during a code review.
   Path: packages/ui/src/features/canvas/components/WebsiteContext.tsx
   Line: 450-458
   
   Comment:
   **Conflict callout has no action**
   
   The message says "Reload to merge your changes" but there is no button to perform that reload. The user is left in edit mode with their draft and a stale `baseVersion`, unable to proceed except by clicking "Discard" and manually re-entering their changes. Consider adding a "Reload" button that calls `queryClient.invalidateQueries` on the instructions key and re-seeds the draft — or at minimum change the message to "Discard your changes and reload to see the latest version" to match the only available action.
   
   How can I resolve this? If you propose a fix, please make it concise.

   Note: If this suggestion doesn't match your team's coding style, reply to this and let me know. I'll remember it for next time!

Prompt To Fix All With AI

Fix the following 2 code review issues. Work through them one at a time, proposing concise fixes.

---

### Issue 1 of 2
packages/ui/src/features/canvas/components/WebsiteContext.tsx:234
Saving empty content is possible when the user manually switches to edit mode via the SegmentedControl (bypassing the EmptyState "Create CONTEXT.md" button). In that case `hasDraft` is `false` and `hasInstructions` is `false`, so disabled evaluates to `false`, and clicking "Save new version" publishes an empty string. After the save, `hasInstructions` is still `false` (empty string trims to nothing), so the component re-renders the EmptyState — creating a ghost version with no content.

```suggestion
              disabled={isPublishing || (hasInstructions ? !hasDraft : draft.trim().length === 0)}
```

### Issue 2 of 2
packages/ui/src/features/canvas/components/WebsiteContext.tsx:450-458
**Conflict callout has no action**

The message says "Reload to merge your changes" but there is no button to perform that reload. The user is left in edit mode with their draft and a stale `baseVersion`, unable to proceed except by clicking "Discard" and manually re-entering their changes. Consider adding a "Reload" button that calls `queryClient.invalidateQueries` on the instructions key and re-seeds the draft — or at minimum change the message to "Discard your changes and reload to see the latest version" to match the only available action.

_{Reviews (1): Last reviewed commit: "feat(canvas): per-channel CONTEXT.md rep..." | Re-trigger Greptile}

[greptile-apps]

Saving empty content is possible when the user manually switches to edit mode via the SegmentedControl (bypassing the EmptyState "Create CONTEXT.md" button). In that case hasDraft is false and hasInstructions is false, so disabled evaluates to false, and clicking "Save new version" publishes an empty string. After the save, hasInstructions is still false (empty string trims to nothing), so the component re-renders the EmptyState — creating a ghost version with no content.

Suggested change

	disabled={isPublishing || (!hasDraft && hasInstructions)}
	disabled={isPublishing || (hasInstructions ? !hasDraft : draft.trim().length === 0)}

Prompt To Fix With AI

This is a comment left during a code review.
Path: packages/ui/src/features/canvas/components/WebsiteContext.tsx
Line: 234

Comment:
Saving empty content is possible when the user manually switches to edit mode via the SegmentedControl (bypassing the EmptyState "Create CONTEXT.md" button). In that case `hasDraft` is `false` and `hasInstructions` is `false`, so disabled evaluates to `false`, and clicking "Save new version" publishes an empty string. After the save, `hasInstructions` is still `false` (empty string trims to nothing), so the component re-renders the EmptyState — creating a ghost version with no content.

```suggestion
              disabled={isPublishing || (hasInstructions ? !hasDraft : draft.trim().length === 0)}
```

How can I resolve this? If you propose a fix, please make it concise.

[github-actions]

React Doctor could not complete this scan.

No React dependency found in /tmp/react-doctor-baseline-971Bm8/package.json. Add "react" to dependencies (or peerDependencies) and re-run.

_{Reviewed by React Doctor for commit 480484c.}