sessions: move account widget to titlebar with entitlement-aware badges (#307243)

* sessions: move account widget to titlebar with entitlement-aware badges

Move the account section from the sidebar footer to the titlebar in the
sessions/agents app, providing a more prominent and accessible location
for account status and Copilot entitlement information.

Key changes:
- Add TitleBarAccountWidget with entitlement-aware dot badges (orange
  for low tokens, red for quota exceeded)
- Add TitleBarUpdateWidget positioned between separator and account icon
- Create accountTitleBarState.ts pure state machine for badge/icon/kind
- Reuse existing ChatStatusDashboard and UpdateHoverWidget in hover panel
- Move 'Open in VS Code' to TitleBarSessionMenu (left of separator)
- Remove old sidebar footer AccountWidget and its fixture
- Add unit tests for the state machine

Layout: [session actions] [Open in VS Code] | [Update] [Account]

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* fix: handle AvailableForDownload state and stabilize badge key

- Add downloadUpdate(true) for the normal AvailableForDownload case
  (when canInstall !== false), matching the workbench pattern
- Remove localized label from badge key to avoid brittleness across
  locales; key now uses only source, dotBadge, and badge percent
- Update unit test assertions for new key format

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

---------

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: osortega

src/vs/sessions/contrib/accountMenu/browser/account.contribution.ts

@@ -0,0 +1,169 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+import { Codicon } from '../../../../base/common/codicons.js';
+import { ThemeIcon } from '../../../../base/common/themables.js';
+import { localize } from '../../../../nls.js';
+import { ChatEntitlement, IChatSentiment, IQuotaSnapshot } from '../../../../workbench/services/chat/common/chatEntitlementService.js';
+
+export type AccountTitleBarStateSource = 'account' | 'copilot';
+export type AccountTitleBarStateKind = 'default' | 'accent' | 'warning' | 'prominent';
+
+export interface IAccountTitleBarStateContext {
+	readonly isAccountLoading: boolean;
+	readonly accountName?: string;
+	readonly accountProviderLabel?: string;
+	readonly entitlement: ChatEntitlement;
+	readonly sentiment: Pick<IChatSentiment, 'hidden' | 'disabled' | 'untrusted'>;
+	readonly quotas: {
+		readonly chat?: IQuotaSnapshot;
+		readonly completions?: IQuotaSnapshot;
+	};
+}
+
+export interface IAccountTitleBarState {
+	readonly source: AccountTitleBarStateSource;
+	readonly kind: AccountTitleBarStateKind;
+	readonly icon: ThemeIcon;
+	readonly label: string;
+	readonly ariaLabel: string;
+	readonly badge?: string;
+	readonly dotBadge?: 'warning' | 'error';
+	readonly revealLabelOnHover?: boolean;
+}
+
+export function getAccountTitleBarBadgeKey(state: IAccountTitleBarState): string | undefined {
+	if (!state.dotBadge) {
+		return undefined;
+	}
+
+	return `${state.source}:${state.dotBadge}:${state.badge ?? ''}`;
+}
+
+export function getAccountTitleBarState(context: IAccountTitleBarStateContext): IAccountTitleBarState {
+	if (context.isAccountLoading) {
+		return {
+			source: 'account',
+			kind: 'default',
+			icon: ThemeIcon.modify(Codicon.loading, 'spin'),
+			label: localize('loadingAccount', "Loading Account..."),
+			ariaLabel: localize('loadingAccountAria', "Loading account"),
+			revealLabelOnHover: true,
+		};
+	}
+
+	const copilotState = getCopilotPresentation(context.entitlement, context.sentiment, context.quotas);
+	if (copilotState) {
+		return copilotState;
+	}
+
+	if (context.accountName) {
+		return {
+			source: 'account',
+			kind: 'default',
+			icon: Codicon.account,
+			label: context.accountName,
+			revealLabelOnHover: true,
+			ariaLabel: context.accountProviderLabel
+				? localize('accountSignedInAria', "Signed in as {0} with {1}", context.accountName, context.accountProviderLabel)
+				: localize('accountSignedInAriaNameOnly', "Signed in as {0}", context.accountName),
+		};
+	}
+
+	return {
+		source: 'account',
+		kind: 'prominent',
+		icon: Codicon.account,
+		label: localize('signInLabel', "Sign In"),
+		ariaLabel: localize('signInAria', "Sign in to your account"),
+	};
+}
+
+function getCopilotPresentation(
+	entitlement: ChatEntitlement,
+	sentiment: Pick<IChatSentiment, 'hidden' | 'disabled' | 'untrusted'>,
+	quotas: { readonly chat?: IQuotaSnapshot; readonly completions?: IQuotaSnapshot }
+): IAccountTitleBarState | undefined {
+	if (sentiment.hidden) {
+		return undefined;
+	}
+
+	if (entitlement === ChatEntitlement.Unknown) {
+		return {
+			source: 'copilot',
+			kind: 'prominent',
+			icon: Codicon.account,
+			label: localize('copilotSignedOut', "Copilot Signed Out"),
+			ariaLabel: localize('copilotSignedOutAria', "GitHub Copilot is signed out"),
+		};
+	}
+
+	if (sentiment.disabled || sentiment.untrusted) {
+		return {
+			source: 'copilot',
+			kind: 'warning',
+			icon: Codicon.account,
+			label: localize('copilotUnavailable', "Copilot Unavailable"),
+			ariaLabel: sentiment.untrusted
+				? localize('copilotUnavailableUntrustedAria', "GitHub Copilot is unavailable in untrusted workspaces")
+				: localize('copilotUnavailableDisabledAria', "GitHub Copilot is disabled"),
+		};
+	}
+
+	const chatQuotaExceeded = quotas.chat?.percentRemaining === 0;
+	const completionsQuotaExceeded = quotas.completions?.percentRemaining === 0;
+	if (entitlement === ChatEntitlement.Free && (chatQuotaExceeded || completionsQuotaExceeded)) {
+		return {
+			source: 'copilot',
+			kind: 'warning',
+			icon: Codicon.account,
+			label: localize('copilotQuotaReached', "Quota Reached"),
+			dotBadge: 'error',
+			ariaLabel: getQuotaReachedAriaLabel(chatQuotaExceeded, completionsQuotaExceeded),
+		};
+	}
+
+	const remainingPercent = getLowestPositivePercent(quotas.chat, quotas.completions);
+	if (entitlement === ChatEntitlement.Free && typeof remainingPercent === 'number' && remainingPercent <= 25) {
+		return {
+			source: 'copilot',
+			kind: remainingPercent <= 10 ? 'warning' : 'accent',
+			icon: Codicon.account,
+			label: localize('copilotTokensRemaining', "Tokens Remaining"),
+			badge: `${remainingPercent}%`,
+			dotBadge: remainingPercent <= 10 ? 'error' : 'warning',
+			ariaLabel: localize('copilotTokensRemainingAria', "{0}% GitHub Copilot tokens remaining", remainingPercent),
+		};
+	}
+
+	return undefined;
+}
+
+function getLowestPositivePercent(...quotas: Array<IQuotaSnapshot | undefined>): number | undefined {
+	let lowest: number | undefined;
+	for (const quota of quotas) {
+		if (typeof quota?.percentRemaining !== 'number' || quota.percentRemaining <= 0) {
+			continue;
+		}
+
+		lowest = typeof lowest === 'number'
+			? Math.min(lowest, quota.percentRemaining)
+			: quota.percentRemaining;
+	}
+
+	return lowest;
+}
+
+function getQuotaReachedAriaLabel(chatQuotaExceeded: boolean, completionsQuotaExceeded: boolean): string {
+	if (chatQuotaExceeded && completionsQuotaExceeded) {
+		return localize('copilotAllQuotaReachedAria', "GitHub Copilot chat and inline suggestion quota reached");
+	}
+
+	if (chatQuotaExceeded) {
+		return localize('copilotChatQuotaReachedAria', "GitHub Copilot chat quota reached");
+	}
+
+	return localize('copilotCompletionsQuotaReachedAria', "GitHub Copilot inline suggestion quota reached");
+}