feat(channels): replace Home canvas with a static channel homepage

[raquelmsmith]

Problem

Each channel auto-created a "Home" canvas as its landing surface. We want the channel landing to be a static, chat-like homepage instead — somewhere to see recent work and kick off a new task — not a generated canvas.

Why: @raquelmsmith asked to turn the channel Home from a canvas into a static page: clicking the channel name should expand the sidebar and open a homepage with a heading, a prompt box, a CONTEXT.md opener, and a Slack-style stack of recent tasks/canvases. No more auto-created Home canvas.

Changes

• New static channel homepage at /website/$channelId (the channel index), replacing the auto-created Home canvas:
  • "What can I do for you today?" heading that fades as the recent list scrolls up.
  • A chat-like stack of the channel's recent tasks + canvases, most recent at the bottom against the composer, pinned to the bottom on load (older items + heading scroll up like Slack history).
  • A prompt box (ChannelHomeComposer) that files a new task into the channel, reusing the real task-creation pipeline (repo-less). A muted "See suggestions" toggle reveals the same starter-prompt cards used on the new-task screen.
  • A CONTEXT.md button pinned to the far right of the top nav bar.
• Clicking a channel name in the sidebar now expands it in the tree and opens the homepage (no longer opens/creates a Home canvas).
• New channels no longer create a Home canvas — they just open the homepage.
• The canvases grid moved to its own /website/$channelId/canvases sub-route (the channel index used to be the grid). The home-canvas service/hooks are left intact for back-compat with existing channels.
• New analytics surface channel_home.
• Drive-by build fix: FolderPicker imported toast from sonner, which was removed from the repo and broke the build — repointed it at the repo toast primitive.

How did you test this?

• pnpm --filter @posthog/ui typecheck — no new type errors from these changes.
• pnpm --filter @posthog/web build — succeeds and bundles the new components/routes (it was failing before the sonner fix).
• Biome check clean on all changed files.
• Not yet manually clicked through in the running app.

Automatic notifications

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

---

Created with PostHog Code

[github-actions]

React Doctor found 4 issues in 2 files · 4 warnings.

4 warnings

src/features/canvas/components/ChannelHomeComposer.tsx

• ⚠️ src/features/canvas/components/ChannelHomeComposer.tsx:6 React 19 API migration can break callers no-react19-deprecated-apis
• ⚠️ src/features/canvas/components/ChannelHomeComposer.tsx:234 JSX element passed as a prop jsx-no-jsx-as-prop
• ⚠️ src/features/canvas/components/ChannelHomeComposer.tsx:244 JSX element passed as a prop jsx-no-jsx-as-prop

src/features/canvas/components/WebsiteChannelHome.tsx

• ⚠️ src/features/canvas/components/WebsiteChannelHome.tsx:132 Chained array iterations js-combine-iterations

_{Reviewed by React Doctor for commit 45e2ca5.}

[greptile-apps]

_{Reviews (1): Last reviewed commit: "feat(channels): replace Home canvas with..." | Re-trigger Greptile}

[greptile-apps]

setAdapter is a new arrow function on every render and is passed directly as onAdapterChange to UnifiedModelSelector. If that component uses React.memo, this will defeat memoisation and cause unnecessary re-renders of the model selector on every keystroke or state change in the parent. Wrapping it in useCallback keeps the reference stable.

Suggested change

	const adapter = lastUsedAdapter;
	const setAdapter = (next: AgentAdapter) => setLastUsedAdapter(next);
	const adapter = lastUsedAdapter;
	const setAdapter = useCallback(
	(next: AgentAdapter) => setLastUsedAdapter(next),
	[setLastUsedAdapter],
	);

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!