Summary

Closes #93041.

• Fix classification: Root-cause bug fix for the Control UI chat sidebar quota rendering regression.
• Maintainer-ready confidence: High. The change is limited to one render gate plus sidebar grid areas, and the affected expanded/collapsed sidebar states are covered by focused unit tests and browser E2E proof.
• Patch quality notes: Focused XS/S diff; production behavior changes in ui/src/ui/chat/session-controls.ts and ui/src/styles/chat/layout.css are paired with regression coverage in ui/src/ui/views/chat.test.ts and ui/src/ui/e2e/chat-quota-pill-93041.e2e.test.ts. No fallback, catch-all, config, auth, provider routing, or quota data-path changes were added.
• Risk labels considered: merge-risk: session-state, because session-controls.ts is a chat/session control surface. No actual session identity, persistence, or switching state is changed; this only changes whether an already-computed informational quota link renders in the sidebar.

What Problem This Solves

After the 2026.6.6 chat layout change, the expanded Control UI chat sidebar stopped showing the OpenAI/Codex provider usage pill. The sidebar still received provider usage data through models.authStatus, but the chat session selector was rendered in sessionSwitcherOnly mode and discarded the quota pill before rendering the sidebar markup.

Users who rely on the Control UI chat sidebar to monitor OpenAI/Codex 5h/weekly limits can see the Usage pill again without changing model selection, session switching, /usage, or provider auth behavior.

Related context: #94219 is an existing open PR for the same issue. This PR keeps the same narrow owner boundary: render gating + sidebar layout + regression proof only.

Root Cause

• Root cause: The 2026.6.6 sidebar chat layout calls renderChatSessionSelect(...) with sessionSwitcherOnly: true so the sidebar shows only session switching UI. renderChatSessionSelect used that same flag to suppress both the model selector and renderChatQuotaPill(state), so valid OpenAI/Codex usage windows from models.authStatus were discarded before markup reached the expanded sidebar.
• Why this is root-cause fix: The source invariant is that sessionSwitcherOnly should hide controls used to switch model/session settings, while the provider quota pill is informational navigation to Usage. Gating the quota pill on compact instead restores it anywhere there is enough sidebar space and still keeps the collapsed 44px rail clean. Adding explicit quota grid rows to the sidebar session-switcher layout gives the restored pill a deterministic slot instead of relying on implicit CSS placement.
• Architecture / source-of-truth check: The source-of-truth render owner is renderChatSessionSelect plus its chat-controls__session-row CSS. The quota data source remains collectQuotaWindowsFromAuthStatus(...) / renderChatQuotaPill(...); no OpenAI/Codex OAuth status, provider routing, /usage, or Gateway protocol contract is changed.
• What did NOT change: No quota collection behavior, model auth status loading, /status, /usage, provider credentials, model routing, session switching RPCs, or model selector behavior changed. sessionSwitcherOnly still hides the model selector, and compact/collapsed sidebar mode still hides the quota pill.

Why This Change Was Made

The quota pill is informational navigation to Usage, not a model/session control. This keeps sessionSwitcherOnly hiding the model selector, but allows the quota pill to render whenever the session switcher is not compact/collapsed. The compact 44px sidebar still omits the pill because there is no space for it.

The sidebar session-switcher CSS grid also now has explicit quota rows for both agent+session and single-session layouts. Without those grid areas, a restored quota pill would not have a deterministic slot in the sidebar stack.

User Impact

• Why it matters / User impact: Users with monitored provider usage windows, including OpenAI/Codex OAuth usage, see the Usage quota pill again in the expanded Control UI chat sidebar and can click it to open Usage. Users with the collapsed sidebar or without provider usage windows see no new pill.

Evidence

See the real behavior proof and regression test plan below. All commands were run after the patch against the committed code path and exited 0.

Real behavior proof

• Behavior or issue addressed: Restores the OpenAI/Codex provider usage quota pill in the expanded Control UI chat sidebar while preserving the compact/collapsed sidebar behavior.

• Real environment tested: Windows/Git Bash task worktree, Node v22.17.0, pnpm 11.2.2. The repo emitted its existing engine warning (wanted: {"node": ">=22.19.0"}) during pnpm commands; the commands below still exited 0.

• Exact steps or command run after this patch:

  node scripts/run-vitest.mjs ui/src/ui/views/chat.test.ts
  node scripts/run-vitest.mjs ui/src/ui/e2e/chat-quota-pill-93041.e2e.test.ts
  node scripts/run-tsgo.mjs -p test/tsconfig/tsconfig.test.ui.json --incremental --tsBuildInfoFile .artifacts/tsgo-cache/test-ui.tsbuildinfo
  pnpm ui:build
  pnpm format:check ui/src/ui/chat/session-controls.ts ui/src/ui/views/chat.test.ts ui/src/ui/e2e/chat-quota-pill-93041.e2e.test.ts ui/src/styles/chat/layout.css
  

• Evidence after fix: Focused chat test exited 0 and asserts the expanded sidebar sessionSwitcherOnly: true render includes [data-chat-provider-usage="true"], keeps [data-chat-model-select="true"] hidden, and compact sidebar mode omits the quota pill. Browser E2E exited 0; with mocked models.authStatus provider usage, it waits for both .sidebar-session-select [data-chat-provider-usage="true"] and .agent-chat__composer-controls [data-chat-provider-usage="true"] to be visible, then verifies the sidebar pill links to /usage and mentions Codex. UI test typecheck exited 0. pnpm ui:build exited 0 and Vite completed with ✓ built in 2.28s. Formatter check exited 0 with All matched files use the correct format.

• Observed result after fix: The real browser Control UI render path now exposes the quota pill under .sidebar-session-select when mocked Gateway auth status reports Codex usage windows, while the existing composer pill remains visible. The focused render test also confirms compact sidebar mode produces no quota pill.

• What was not tested: A live OAuth-connected OpenAI account showing real account percentages was not available in this environment. The production quota data path is unchanged; the regression proof uses the existing mocked Gateway models.authStatus E2E fixture to exercise the real browser Control UI render path.

SonarLint/Sonar scanner note: no sonarlint or sonar-scanner executable was available on PATH in this environment, so no local Sonar scan was run.

Regression Test Plan

• Target test file: ui/src/ui/views/chat.test.ts and ui/src/ui/e2e/chat-quota-pill-93041.e2e.test.ts.
• Scenario locked in: Provider usage from mocked models.authStatus renders the quota pill in the expanded sidebar session switcher while sessionSwitcherOnly still hides the model selector; compact/collapsed sidebar mode does not render the pill.
• Why this is the smallest reliable guardrail: The unit test locks the exact render gate that regressed and the compact exception. The browser E2E locks the user-visible Control UI sidebar path without requiring a real OAuth account, while the unchanged quota collection path keeps provider/auth behavior outside this PR.

Merge risk

• Risk explanation: The only merge-risk signal is the session-state category from touching session-controls.ts; the patch does not mutate session keys, switch sessions, persist state, or change Gateway/session RPC payloads. Layout risk is limited to the sidebar session switcher when quota data exists.
• Why acceptable: The restored quota pill uses the existing renderChatQuotaPill output and /usage link, and the CSS adds explicit quota grid rows for the expanded sidebar layouts. Focused tests cover expanded sidebar display, model-selector suppression, compact-sidebar hiding, and browser-visible sidebar rendering.