diff --git a/src/@types/vscode.proposed.chatParticipantPrivate.d.ts b/src/@types/vscode.proposed.chatParticipantPrivate.d.ts
index e5a1abb3cc..9cbc18c074 100644
--- a/src/@types/vscode.proposed.chatParticipantPrivate.d.ts
+++ b/src/@types/vscode.proposed.chatParticipantPrivate.d.ts
@@ -468,4 +468,55 @@ declare module 'vscode' {
 		 */
 		readonly fullReferenceName?: string;
 	}
+
+	// #region Quota Sync
+
+	/**
+	 * A snapshot of quota usage for a single category (chat, completions, premium chat).
+	 */
+	export interface ChatQuotaSnapshot {
+		readonly percentRemaining: number;
+		readonly unlimited: boolean;
+		readonly hasQuota?: boolean;
+		readonly resetAt?: number;
+		readonly usageBasedBilling?: boolean;
+		readonly entitlement?: number;
+		readonly quotaRemaining?: number;
+	}
+
+	/**
+	 * A snapshot of rate limit usage for a category (session or weekly).
+	 */
+	export interface ChatRateLimitSnapshot {
+		readonly percentRemaining: number;
+		readonly unlimited: boolean;
+		readonly resetDate?: string;
+	}
+
+	/**
+	 * Quota snapshot data covering all categories.
+	 * Accepted by {@link chat.updateQuotas} for extension-to-core sync.
+	 */
+	export interface ChatQuotaSnapshots {
+		readonly resetDate?: string;
+		readonly resetDateHasTime?: boolean;
+		readonly usageBasedBilling?: boolean;
+		readonly canUpgradePlan?: boolean;
+		readonly chat?: ChatQuotaSnapshot;
+		readonly completions?: ChatQuotaSnapshot;
+		readonly premiumChat?: ChatQuotaSnapshot;
+		readonly additionalUsageEnabled?: boolean;
+		readonly additionalUsageCount?: number;
+		readonly sessionRateLimit?: ChatRateLimitSnapshot;
+		readonly weeklyRateLimit?: ChatRateLimitSnapshot;
+	}
+
+	export namespace chat {
+		/**
+		 * Push quota snapshot data from the extension to the core workbench.
+		 */
+		export function updateQuotas(quotas: ChatQuotaSnapshots): void;
+	}
+
+	// #endregion
 }
diff --git a/src/@types/vscode.proposed.chatSessionsProvider.d.ts b/src/@types/vscode.proposed.chatSessionsProvider.d.ts
index b46ec3015d..386bea6d01 100644
--- a/src/@types/vscode.proposed.chatSessionsProvider.d.ts
+++ b/src/@types/vscode.proposed.chatSessionsProvider.d.ts
@@ -336,6 +336,26 @@ declare module 'vscode' {
 		 */
 		archived?: boolean;
 
+		/**
+		 * Resource identifier this item was previously known by. When set, host-stored
+		 * per-resource state (archive, pin, read) recorded under that URI is treated as
+		 * also applying to this item.
+		 *
+		 * On first access of state for {@link resource}, the host adopts the entry
+		 * stored under `legacyResource` forward - copying it onto {@link resource} and
+		 * removing the legacy entry. The migration is transparent: no events fire and
+		 * the effective user-visible state is unchanged.
+		 *
+		 * Intended for providers that need to change the URI shape they emit (e.g. during
+		 * a backend or schema migration) without requiring users to re-archive or re-pin
+		 * items.
+		 *
+		 * The legacy URI's scheme must match {@link resource}'s scheme; otherwise the
+		 * field is ignored. Multi-hop migrations are not supported - providers should
+		 * collapse intermediate hops on their side and emit the original URI.
+		 */
+		readonly legacyResource?: Uri;
+
 		/**
 		 * Timing information for the chat session
 		 */
@@ -658,6 +678,48 @@ declare module 'vscode' {
 		 * unique across the provider's groups; on conflict, the first declared wins.
 		 */
 		readonly slashCommand?: string;
+
+		/**
+		 * Optional tooltip content shown in a hover panel when the user focuses or
+		 * hovers over this item in the picker. Supports markdown formatting.
+		 */
+		readonly tooltip?: string;
+
+		/**
+		 * Optional model metadata for this option item. When present, the picker
+		 * renders a rich hover with model name, pricing, context size, and capabilities
+		 * instead of a plain text tooltip.
+		 */
+		readonly modelMetadata?: ChatSessionProviderOptionModelMetadata;
+	}
+
+	/**
+	 * Metadata describing a language model, used to render rich hover content
+	 * in option group pickers. Fields mirror {@link LanguageModelChatInformation}
+	 * so the core can reuse its standard model hover rendering.
+	 */
+	export interface ChatSessionProviderOptionModelMetadata {
+		readonly name: string;
+		readonly id: string;
+		readonly vendor?: string;
+		readonly version?: string;
+		readonly family?: string;
+		readonly tooltip?: string;
+		readonly pricing?: string;
+		readonly multiplierNumeric?: number;
+		readonly inputCost?: number;
+		readonly outputCost?: number;
+		readonly cacheCost?: number;
+		readonly longContextInputCost?: number;
+		readonly longContextOutputCost?: number;
+		readonly longContextCacheCost?: number;
+		readonly priceCategory?: string;
+		readonly maxInputTokens?: number;
+		readonly maxOutputTokens?: number;
+		readonly capabilities?: {
+			readonly vision?: boolean;
+			readonly toolCalling?: boolean;
+		};
 	}
 
 	/**
diff --git a/src/github/pullRequestGitHelper.ts b/src/github/pullRequestGitHelper.ts
index 0fe25edf0f..cb49963292 100644
--- a/src/github/pullRequestGitHelper.ts
+++ b/src/github/pullRequestGitHelper.ts
@@ -333,8 +333,16 @@ export class PullRequestGitHelper {
 		try {
 			const configKey = this.getMetadataKeyForBranch(branchName);
 			const allConfigs = await repository.getConfigs();
-			const matchingConfigs = allConfigs.filter(config => config.key === configKey).sort((a, b) => b.value < a.value ? 1 : -1);
-			return PullRequestGitHelper.parsePullRequestMetadata(matchingConfigs[0].value);
+			// When the same branch name has been associated with multiple PRs over
+			// time (resulting in duplicate config entries), prefer the most recent
+			// association: parse the trailing PR number and sort numerically so the
+			// highest PR number wins. Falls back to the first entry if no match.
+			const matchingConfigs = allConfigs
+				.filter(config => config.key === configKey)
+				.map(config => ({ config, metadata: PullRequestGitHelper.parsePullRequestMetadata(config.value) }))
+				.filter((entry): entry is { config: { key: string; value: string }, metadata: PullRequestMetadata } => !!entry.metadata)
+				.sort((a, b) => b.metadata.prNumber - a.metadata.prNumber);
+			return matchingConfigs[0]?.metadata;
 		} catch (_) {
 			return;
 		}
diff --git a/src/test/github/pullRequestGitHelper.test.ts b/src/test/github/pullRequestGitHelper.test.ts
index 590b35f0aa..4a4a8b9f45 100644
--- a/src/test/github/pullRequestGitHelper.test.ts
+++ b/src/test/github/pullRequestGitHelper.test.ts
@@ -188,4 +188,27 @@ describe('PullRequestGitHelper', function () {
 			assert.strictEqual(await repository.getConfig('branch.pr/me/100.github-pr-owner-number'), 'owner#name#100');
 		});
 	});
+
+	describe('getMatchingPullRequestMetadataForBranch', function () {
+		it('returns the highest-numbered PR when duplicate config entries exist for the branch', async function () {
+			// Simulate the case where a branch name has been associated with multiple
+			// PRs over time and `git config --get-all` returns duplicate entries.
+			// The helper should prefer the most recent association (highest PR
+			// number for the same owner/repo), not the lowest.
+			sinon.stub(repository, 'getConfigs').resolves([
+				{ key: 'branch.feature.github-pr-owner-number', value: 'owner#name#5' },
+				{ key: 'branch.feature.github-pr-owner-number', value: 'owner#name#42' },
+				{ key: 'branch.feature.github-pr-owner-number', value: 'owner#name#17' },
+				{ key: 'branch.other.github-pr-owner-number', value: 'owner#name#999' },
+			]);
+
+			const metadata = await PullRequestGitHelper.getMatchingPullRequestMetadataForBranch(repository, 'feature');
+
+			assert.deepStrictEqual(metadata, {
+				owner: 'owner',
+				repositoryName: 'name',
+				prNumber: 42,
+			});
+		});
+	});
 });
diff --git a/src/view/reviewManager.ts b/src/view/reviewManager.ts
index 38bc2b3341..bc8d45db43 100644
--- a/src/view/reviewManager.ts
+++ b/src/view/reviewManager.ts
@@ -428,7 +428,17 @@ export class ReviewManager extends Disposable {
 	private async getUpstreamUrlAndName(branch: Branch): Promise<{ remoteUrl: string | undefined, upstreamBranchName: string | undefined, remoteName: string | undefined }> {
 		if (branch.upstream) {
 			Logger.debug(`Upstream for branch ${branch.name} is ${branch.upstream.remote}/${branch.upstream.name}`, this.id);
-			return { remoteName: branch.upstream.remote, upstreamBranchName: branch.upstream.name, remoteUrl: undefined };
+			// When a branch is created tracking a different remote branch (e.g. via
+			// `git worktree add -b feature-foo <path> origin/develop`), git sets
+			// `branch.<name>.merge` to the upstream's branch (`develop`) even though
+			// the eventual PR head ref is the local branch name (`feature-foo`).
+			// Prefer the local branch name when it differs from the tracked upstream,
+			// since GitHub PR `headRefName` matches the pushed branch name, which
+			// defaults to the local branch name.
+			const upstreamBranchName = (branch.name && branch.upstream.name !== branch.name)
+				? branch.name
+				: branch.upstream.name;
+			return { remoteName: branch.upstream.remote, upstreamBranchName, remoteUrl: undefined };
 		} else {
 			try {
 				const remoteUrl = await this.repository.getConfig(`branch.${branch.name}.remote`);