Open channel Canvas from the channel menu in a side-pane tab

[jameskraus]

On main, Channel actions → View canvas opens Canvas as a modal over the conversation. This PR makes Canvas a bundled plugin whose menu item opens it as a tab in the side pane, so the conversation stays visible while you edit.

Demo

canvas-tabs-demo.mp4

Recorded at 330c3636e with the browser-test fixture, against a synthetic relay. "Channel actions unavailable" in the menu comes from the fixture.

Behavior

• Channel actions → View canvas opens Canvas in a side-pane tab. If Canvas is already open, the item selects its tab. Solo chats keep Canvas in Chat settings.
• Saving keeps Canvas open. Closing the tab returns to the remaining tab.
• Leaving the channel closes its Canvas tab, because Canvas is bound to its channel and visit (see docs/channels.md). The draft is kept and comes back when you reopen it.
• Closing Canvas while a save is in flight leaves no stale draft.
• A slow load never takes focus from the composer. Retry loading and Discard and reload keep focus on their pending button, then hand it to the editor when the read lands, unless focus has moved elsewhere.
• The item appears only for members of writable, unarchived channels, and only while the Canvas plugin is enabled.
• Edit, History, conflict handling and restore are unchanged.

Changes

• src/bundled/canvas. A new buzz.canvas plugin, on by default, registers a channelMenu panel, the same contract Channel Usage uses. It also holds the editor, which is the former channels/ChannelCanvasDialog without its modal wrapper.
• ChannelHeaderMenu and ChannelsPage. The hardcoded View canvas item and the modal state are gone. Canvas arrives through the menu-panel list the channel menu already receives.
• crates/plugin-manager. buzz.canvas is in the native catalog and enabled by default.
• Docs. docs/channels.md and docs/plugin-architecture.md describe View canvas as a menu panel.

Not chosen

• A header button that opens the tab. Header launchers open their tool's drawer, as Todos and Terminal do. A launcher that opens a tab would need a new hook in the shared tab host, while the menu-panel contract already handles the entry, eligibility, tab and focus.
• Blocking tab close during a save. Changing channel, browser back/forward, Cmd/Ctrl+W and disabling the plugin can't be blocked. Instead, a save retires its draft when the write lands. replaceView guards that clear, so a newer draft is never lost.

Tests

• Vitest (canvas/CanvasEditor.test.tsx) covers these cases:
  • Editing continues after a save.
  • A save or restore that lands after close retires its draft. Fails without the fix.
  • A reopened editor's newer draft survives.
  • A slow load leaves focus where the user moved it. Fails without the fix.
  • Retry and confirmed reload keep focus while pending and hand it to the editor, including when the read lands while the confirmation is still closing. Fails without the fix.
• Rust. native_catalog_matches_desktop_bundles covers the catalog entry.
• Browser journeys (Chromium and WebKit):
  • Added: channel-tabs.spec.mjs › Canvas opens once beside Thread and retains its channel draft. It needs a browser for the real plugin registration, menu, tab focus and channel switching. It fails on main, where no Canvas tab appears, and passes here.
  • Removed: none.
  • Updated from modal to tab assertions: canvas-history, channel-header-menu and channel-modal-dismissal.

Readiness

Draft. Agent-review findings are addressed. Human testing in the app remains before this can be marked ready.

Known gaps

• The native desktop build and writes to a live relay are not exercised.
• Menu-panel items share a generic info icon, so View canvas has no file icon. That is a design call.

[wesbillman]

🤖 Star Lord's automated source review via Wes's account, integrating independent Rocket (systems/lifecycle), Mantis (correctness/security/concurrency), and Groot (product/accessibility) lanes.

Reviewed head 76f2cd5b5bff7b9252614971663672ed865a4b86 against base ad7ac95ce73b44be448d9a1285a72e10d9ee7b37.

8/10 — one P2 recovery-focus defect, detailed inline. The existing menu-panel host, session-owned writes, default-enabled browser/native catalogs, and revision-guarded draft retirement fit the stated scope. No additional actionable findings from the other lanes.

Validation: source inspection only; no tests, builds, app launches, or PR code execution. One hosted-check snapshot showed 34 successes and Windows native validation skipped. Reviewed the added tab journey and migrated component/browser coverage; runtime focus, both themes, narrow/enlarged layouts, native/live-relay behavior, performance, comparative test cost, and human acceptance remain unverified. The public description was inspected, but its single demo video could not be decoded here; attachment-content review is incomplete. This COMMENT is not approval or merge authorization.

[wesbillman]

🤖 Star Lord's automated source review via Wes's account, integrating independent Rocket (systems/lifecycle), Mantis (correctness/security/concurrency), and Groot (product/accessibility) lanes.

Reviewed merge head 951c212d46e8f31c973d339251107c203887a43c against base 16ca8d3f8e6225d17863302aee45a43aa425553e, following the review at 76f2cd5b5bff7b9252614971663672ed865a4b86.

8/10 — the existing recovery-focus P2 remains; no new merge-integration findings. The Canvas feature patch is identical apart from Git object index lines, and the merge has no conflict-resolution delta. We checked the upstream tab/menu contracts, panel lifetime and draft-write guards. The unchanged Retry/Discard-and-reload behavior still needs the repair already described in the existing inline finding; it is referenced here without a duplicate inline comment.

Validation: immutable source inspection only; no tests, builds, app launches, or PR code execution. One hosted-check snapshot showed 7 successes, 26 checks running, and Windows validation skipped. Runtime focus, native/live-relay behavior, both themes, narrow/enlarged layouts, performance, comparative test cost, and human acceptance remain unverified. The public description and merge message were inspected; the existing demo video could not be decoded here, so attachment-content review remains incomplete. This COMMENT is not approval or merge authorization.

[wesbillman]

🤖 Star Lord's automated source review via Wes's account, integrating independent Rocket (systems/lifecycle), Mantis (correctness/security/concurrency), and Groot (product/accessibility) lanes.

Reviewed head 5a947e3858d11876972062df0029069a6b8a455f against base 16ca8d3f8e6225d17863302aee45a43aa425553e, focusing on the two-file repair since 951c212d46e8f31c973d339251107c203887a43c.

9/10 — no actionable findings in this follow-up. The previous recovery-focus P2 is addressed: Retry/Reload retains a focusable pending button, successful reads hand focus to the editor only when appropriate, failures retain the recovery control, and the confirmation uses the shared moved-focus guard when the read finishes during dialog exit. The new test cases cover delayed reads, repeated failure, moved focus, and dialog-exit ordering. Existing generation fences and keyed panel lifetime remain intact.

Validation: immutable source and test inspection only; no tests, builds, app launches, or PR code execution. One hosted-check snapshot showed 6 successes, 27 checks running, and Windows validation skipped. Real browser/native focus timing, screen-reader behavior, themes/layouts, live-relay behavior, performance, comparative test cost, and human acceptance remain unverified. Public description and follow-up commit inspected with no disclosure finding; its existing demo video could not be decoded here, so attachment-content review remains incomplete. This COMMENT is not approval or merge authorization.

[wesbillman]

🤖 Star Lord's automated source review via Wes's account, integrating independent Rocket (systems/lifecycle), Mantis (correctness/security/concurrency), and Groot (product/accessibility) lanes.

Reviewed head 330c3636e034383cd2fb09d9762bc5ba6b250835 against base 3d079946e590b56f5560bd816ee0cae7d60cc44e, following the review at 5a947e3858d11876972062df0029069a6b8a455f.

9/10 — no actionable findings in this merge follow-up. Canvas editor and registration source are unchanged from the previously reviewed recovery-focus repair. The current channel menu preserves eligibility checks and panel lifetime; Solo retains Canvas through Chat settings. The updated tab journey reflects that split while retaining channel-switch retirement and draft restoration coverage. No new integration defect was demonstrated.

Validation: immutable source and test inspection only; no tests, builds, app launches, or PR code execution. One hosted-check snapshot was still in progress, with Windows native validation skipped. Browser/native focus timing, screen readers, themes/layouts, live-relay behavior, performance, test-cost comparisons, and human acceptance remain unverified. Public description and merge message inspected with no disclosure finding; the single demo video could not be decoded with available tools, so attachment-content review remains incomplete. This COMMENT is not approval or merge authorization.