fix(desktop): hide the offcanvas-collapsed sidebar so it stops painting over the community rail

[thomaspblock]

Summary

Collapsing the sidebar left a phantom copy of it painted over the community/relay rail — opaquely on flat themes (vesper et al., which made the rail look removed), and as ghost fragments (muted search-box fill, truncated channel-name tails) on the Buzz themes whose chrome is intentionally transparent for the gradient.

Cause: #4281 made the app-sidebar layer overflow-visible (the huddle drawer needs to escape it). That removed the ancestor clipping the offcanvas collapse relied on: the sidebar slides to left: -sidebar-width but kept painting, exactly over the z-0 rail (z-10 sidebar layer).

Fix: the offcanvas-collapsed sidebar container is now invisible + pointer-events-none, with visibility added to the transition list so the 200 ms slide-out still animates and the flip happens only at the transition's end. Theme-independent; no per-theme CSS touched; the huddle drawer's overflow-visible is preserved.

Before / after

Left 420px of the app with the sidebar collapsed. Before = unpatched origin/main @ 69107dc; after = this branch. Same seeded state, same build pipeline (build:e2e between checkouts).

theme	before (ghost sidebar over the rail)	after (rail clean: A / B / + visible)
vesper
buzz
buzz-dark

Before shots: ghost ⌘K search chip + blue active-item pill painted over the rail column; on vesper the opaque panel hides the rail buttons entirely. After: the rail's community buttons (A, B) and + are visible and clickable in all three themes.

Reported by Thomas P in #buzz-bugs: buzz://message?channel=e62570dd-33ad-42c5-b92b-75f2689f9694&id=9ea401ca1d009f555ca4324e136f8d8d8156db2f8afa3ff89fd038d2c16260f7

cc @klopez4212 — this touches the layout your #4281/#5478 work shaped; please confirm it doesn't defeat the huddle drawer or glass intentions. The change deliberately hides only the offcanvas-collapsed container, nothing in the expanded path.

Test plan

• New Playwright regression spec sidebar-offcanvas-rail.spec.ts (buzz / buzz-dark / vesper): collapsed sidebar must be visibility: hidden + pointer-events: none, community rail stays visible and interactive. Fails on unpatched build (verified), passes with the fix.
• Full desktop unit suite: 4,954 pass / 0 fail
• pnpm typecheck, pnpm check (biome + file-size ratchet + px-text + pubkey-truncation) green
• Before/after screenshots above captured via the e2e harness on both builds

[thomaspblock]

Regenerated before/after proof (previous embeds used relay media URLs, which GitHub's camo proxy rejects — this comment uses the repo's post-screenshots.sh immutable hosting).

Left 420px of the app, sidebar collapsed. Before (unpatched origin/main @ 69107dc): the offcanvas sidebar keeps painting over the community rail — ghost ⌘K search chip and blue active-item pill on the left edge; on vesper the opaque panel wipes the rail entirely. After (this PR): the rail's A / B / + buttons are clean and clickable in all three themes.

vesper

before	after

buzz

before	after

buzz-dark

before	after

[wesbillman]

CLEAR at exact head ecfc7fb0c0d058fb402af49e656123b8326c8c2f.

I traced the desktop Sidebar primitive through both consumers (AppSidebar and Settings), the provider state/shortcut path, the community-rail stacking boundary, and the huddle-driven overflow-visible layout. The fix is correctly scoped to desktop collapsible="offcanvas" state: visibility:hidden removes the collapsed subtree from paint, hit testing, keyboard focus, and the accessibility tree; pointer-events:none prevents interception during the 200 ms slide-out before visibility flips. Expanded, icon, non-collapsible, and mobile Sheet paths are unchanged.

The regression runs in the Desktop smoke project across buzz, buzz-dark, and vesper and pins the computed collapsed visibility/pointer-event contract plus rail visibility. One non-blocking test nit: the prose says the rail is interactive, but the test only checks visibility rather than clicking the second community. The computed pointer-events:none assertion directly covers the original interception mechanism, so I do not consider that omission a merge blocker.

Remote PR head matched this clean local review head; git diff --check origin/main...HEAD passed. Exact-head Desktop/E2E/DCO checks are green. No correctness, accessibility, security, privacy, or user-trust finding.

[wesbillman]

Mongo exact-head review at ecfc7fb0c0d058fb402af49e656123b8326c8c2f: code-clear / merge-ready.

I traced both desktop consumers of the shared Sidebar (AppSidebar and SettingsView), the provider's expanded/collapsed state transition, the overflow-visible app-shell ancestry, left/right and offcanvas/icon variants, and the huddle drawer placement. The change is narrowly scoped to the desktop offcanvas-collapsed sliding container: visibility becomes hidden only at the end of the existing 200 ms transition, visible immediately on expansion, and pointer-events: none prevents the offscreen z-10 layer from intercepting the z-0 community rail. It does not alter mobile Sheet behavior, icon collapse, expanded sidebar rendering, or the separately rendered huddle drawer slot.

The regression covers the three materially different theme surfaces and is in the smoke project. Exact-head Desktop Core/build/smoke/integration checks and DCO are green; git diff --check origin/main...HEAD passes. No correctness, accessibility, breakpoint, animation, or huddle regression blocker found.

Non-blocking test hardening: the spec's fixed waitForTimeout(500) can be removed because toHaveCSS("visibility", "hidden") already polls the actual transition completion. Also, the final “interactive” claim would be stronger if it clicked community B and asserted the active marker rather than only checking visibility. Neither weakens confidence in this production patch because the test directly asserts the offending layer is hidden and has pointer-events: none, and the visual before/after proof reproduces the paint defect.

[wesbillman]

Carl, an automated reviewer, commenting via Wes’s GitHub account.

Reviewed the exact head ecfc7fb0c0d058fb402af49e656123b8326c8c2f adversarially across the sidebar state transition, responsive/mobile branch, z-index and overflow ancestry, Huddle drawer boundary, theme behavior, and regression coverage.

No actionable findings. The change is narrowly scoped to the desktop offcanvas-collapsed container: visibility removes its painted and accessibility subtree only after the existing 200 ms exit transition, pointer-events: none prevents the displaced layer from intercepting the community rail, and expanded/icon/mobile paths remain outside the selector. The Huddle drawer remains outside the sidebar container and the overflow-visible shell is preserved.

Independent verification on the clean exact-head worktree:

• pnpm build:e2e
• pnpm exec playwright test tests/e2e/sidebar-offcanvas-rail.spec.ts --project=smoke → 3/3 passed (buzz, buzz-dark, vesper)
• git diff --check 69107dc3bfecbb80cc5f5b8bb6a7647ad054ce57..HEAD

I also confirmed all current GitHub checks for this head are completed successfully or intentionally skipped. I did not approve because Wes did not request an approval review.