feat(channels): collapsible sidebar groups, # icons, two-step create, context→channel rename

[adamleithp]

Continues the channels (Project Bluebird) surface work. Grouped by area:

Rename: context → channel

• User-facing copy only — no types, no analytics wire strings, no backend fields.
• Sidebar heading, empty state, star/rename/delete labels, delete-confirm dialog and its toasts.
• Channel intro card: "created this channel", "beginning of the X channel", "Learn more about channels".
• Create/rename modals, activity view, command palette group, sidebar nav row, browser-tab fallback label, channel header fallback.
• contextPrompt.ts — the agent prompt now says Build a CONTEXT.md for the channel "X" (was "context/folder"). This was the highest-leverage one: it was teaching the model the stale noun, seeding it into every generated CONTEXT.md.
• Deliberately untouched: context.md itself, ANALYTICS_EVENTS.CONTEXT_ACTION / context_md_building / context_name (renaming would split existing PostHog insights and break old feed rows), and identifiers like channelContext / ContextMdState that mean the file, not the channel.

Sidebar: collapsible groups

• "Starred" and "Channels" are now collapsible; the whole header row is the trigger.
• Rests as a #, swaps to a chevron on hover/focus.
• Collapse state persists per section in the shared sidebar store, keyed channels:* to stay clear of the Code sidebar's folder keys.
• Uses Base UI's Collapsible directly, not quill's: quill styles its trigger as a button (which fought the MenuLabel styling these headers had) and animates panel height, which janked against a long list.
• Panel is keepMounted. Each row builds a context menu, dropdown, tooltip and two dialogs up front, so the default unmount-on-close made every expand rebuild the lot — ~940ms → ~75ms for 46 channels (collapsing was always ~80ms).

Icons

• Every remaining SquircleDashed → # (phosphor HashIcon), across channel rows, #me, group headers, channel header, breadcrumb, rename field, command palette and browser tabs. lucide-react dropped from those files.

Create flow

• Floating + button bottom-right of the channel list (tooltip "Create something new"), menu opens upward with New channel / New task. Replaces the small + beside the "Channels" label.
• + added to the #me row, matching the other channels. The me folder is created lazily, so its actions resolve the id at click time rather than closing over it — hence the optional call-time channelId override on useCreateAndOpenDashboard (without it, "New canvas" on a never-opened #me silently no-ops against a stale undefined).
• Channel creation split into two steps: name → Next, then "What's this channel about?" → Skip / Create.
• Step two is a real nested dialog, so quill scales and dims step one behind it — the stack itself is the affordance that says there's another step. Escape returns to the name, intact. The nesting offset is inverted from quill's default so step one peeks above rather than below.
• Nothing is created until step two resolves: Create = channel + CONTEXT.md plan session; Skip = channel alone (its intro card still offers CONTEXT.md later).

Fix: empty-state flash on channel creation

• Creating a channel flashed the old welcome + suggestions screen before the feed appeared.
• WebsiteChannelHome took only channel from useBackendChannel and dropped its isLoading. A new channel resolves its backend channel over the network (a resolve-or-create POST); for that whole window there was no intro (it needs backendChannel), no tasks, and — because the feed query is disabled until the id exists, and a disabled react-query reports isLoading: false — the view believed it wasn't loading. So ChannelFeedView fell through to emptyState.
• Fix folds the identity resolution into the loading flag: a channel isn't empty until we know which channel it is.
• A plain reload never showed this, because the backend channels list is already cached by the time the view mounts.

Testing

• Typecheck, biome, and the canvas/browser-tabs/command test suites pass.
• Driven against the real app over CDP: FAB menu and both items, the two-step dialog (including measuring that step one sits above step two), the #→chevron hover swap, collapse/expand persistence, and the #me +.
• The flash fix was verified by creating a channel and sampling the visible view every 25ms: now spinner → intro, no empty state at any point. Two throwaway probe channels were created and deleted.

Known gaps

• Sidebar interactions still cost ~650ms+ in dev regardless of this change — opening the FAB alone (local state, no collapsible) measures ~660ms, and the app does ~13.5k re-renders during 3s idle. The whole tree re-renders on any state change and repays 46 expensive rows. Pre-existing and out of scope here; the real fix is building each row's menus/dialogs lazily.
• If the resolve-or-create POST fails permanently you now get a spinner where you previously got the (misleading) suggestions screen. useBackendChannel retries on failure, so it spins rather than settles.

🤖 Generated with Claude Code

https://claude.ai/code/session_019G63f4afY9vsbKsvK654Wj

[trunk-io]

😎 Merged directly without going through the merge queue, as the queue was empty and the PR was up to date with the target branch - details.

[github-actions]

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

2 warnings

src/features/canvas/components/ChannelsList.tsx

• ⚠️ src/features/canvas/components/ChannelsList.tsx:665 Control missing accessible label control-has-associated-label

src/features/canvas/components/CreateChannelModal.tsx

• ⚠️ src/features/canvas/components/CreateChannelModal.tsx:49 Large component is hard to read and change no-giant-component

_{Reviewed by React Doctor for commit df475a8.}

[stamphog]

This is a 777-line feature PR with zero reviews touching meaningful UX behavior (two-step channel-create modal, collapsible sidebar groups, new FAB component, pervasive rename). Zero reviews on a change of this size and scope warrants human sign-off. There is also a visible copy error in the empty state: "No channels other channels yet." needs fixing before ship.

[greptile-apps]

_{Reviews (1): Last reviewed commit: "fix(channels): don't flash the empty sta..." | Re-trigger Greptile}