Fix local PR tree not updating when PR is created on GitHub website

When a PR is created on the GitHub website (not via VS Code UI), the
ReviewManager discovers it via checkGitHubForPrBranch() and associates
the local branch with the PR. However, the local PR tree cache in
PrsTreeModel was never invalidated afterward, so the "Local Pull Request
Branches" category never showed the newly-associated branch.

Fix: In PrsTreeModel's onDidChangeActivePullRequest handler, when the
new active PR is not already in the cached PR set, delete the
LocalPullRequest cache entry and fire a full folder refresh (which
triggers refreshRepo() in the tree data provider) instead of the narrow
PR-level refresh (which only updates existing PR nodes via
refreshPullRequests()).

Agent-Logs-Url: https://github.com/microsoft/vscode-pull-request-github/sessions/a016c47c-ed2e-432f-b461-f678d8ab62c8

Co-authored-by: alexr00 <38270282+alexr00@users.noreply.github.com>

Author: Copilot

src/@types/vscode.proposed.chatSessionsProvider.d.ts

@@ -343,7 +343,7 @@ declare module 'vscode' {
 		/**
 		 * Statistics about the chat session.
 		 */
-		changes?: readonly ChatSessionChangedFile[] | readonly ChatSessionChangedFile2[];
+		changes?: readonly ChatSessionChangedFile[];
 
 		/**
 		 * Arbitrary metadata for the chat session. Can be anything, but must be JSON-stringifyable.
@@ -353,34 +353,7 @@ declare module 'vscode' {
 		metadata?: { readonly [key: string]: any };
 	}
 
-	/**
-	 * @deprecated Use `ChatSessionChangedFile2` instead
-	 */
 	export class ChatSessionChangedFile {
-		/**
-		 * URI of the file.
-		 */
-		modifiedUri: Uri;
-
-		/**
-		 * File opened when the user takes the 'compare' action.
-		 */
-		originalUri?: Uri;
-
-		/**
-		 * Number of insertions made during the session.
-		 */
-		insertions: number;
-
-		/**
-		 * Number of deletions made during the session.
-		 */
-		deletions: number;
-
-		constructor(modifiedUri: Uri, insertions: number, deletions: number, originalUri?: Uri);
-	}
-
-	export class ChatSessionChangedFile2 {
 		/**
 		 * URI of the file.
 		 */
@@ -728,9 +701,18 @@ declare module 'vscode' {
 	export interface ChatSessionInputState {
 		/**
 		 * Fired when the input state is changed by the user.
+		 *
+		 * Move to controller?
 		 */
 		readonly onDidChange: Event<void>;
 
+		/**
+		 * The resource associated with this chat session.
+		 *
+		 * This is `undefined` for chat sessions that have not yet started.
+		 */
+		readonly sessionResource: Uri | undefined;
+
 		/**
 		 * The groups of options to show in the UI for user input.
 		 *

src/view/prsTreeModel.ts

@@ -87,7 +87,18 @@ export class PrsTreeModel extends Disposable {
 				if (e.new) {
 					prs.push({ model: e.new, event: {} });
 				}
-				this._onDidChangeData.fire(prs);
+
+				// When a new active PR is discovered (e.g. PR created on GitHub website),
+				// check if it's already in the local PR cache. If not, clear the local cache
+				// and fire a full folder refresh so the "Local Pull Request Branches" category
+				// picks up the newly-associated branch.
+				if (e.new && !this._allCachedPRs.has(e.new)) {
+					const cache = this.getFolderCache(manager);
+					cache.delete(PRType.LocalPullRequest);
+					this._onDidChangeData.fire(manager);
+				} else {
+					this._onDidChangeData.fire(prs);
+				}
 
 				if (this._activePRDisposables.has(manager)) {
 					disposeAll(this._activePRDisposables.get(manager)!);