feat: add coderm.workbench.openReadme command

README.ja.md

@@ -94,6 +94,7 @@ VS Codeのフォーク。本家にはないUI/UX改善を追加した(してい
 | `coderm.workbench.editor.resizePaneRight` | ペインを右方向にリサイズ |
 | `coderm.workbench.modalEditor.open`       | 空のモーダルエディタを開く |
 | `coderm.workbench.modalEditor.close`      | モーダルエディタを閉じる |
+| `coderm.workbench.openReadme`             | workspaceルートのREADME.mdを開く（なければ新規ファイル） |
 
 > [!TIP]
 > **モーダルエディタ:** モーダルが開いてフォーカスされている間、Quick Open のファイルやエディタ配置のターミナルはモーダル内に直接開きます。モーダル内でターミナル（`lazygit` 等）を動かすには `terminal.integrated.defaultLocation: "editor"` を設定してください（パネルターミナルはモーダルに流入しません）。`coderm.modal.captureContent: false` で、モーダルを閉じてメインへ流す本家挙動に戻せます。

README.md

@@ -94,6 +94,7 @@ Settings unique to Coderm that are not available in upstream VS Code.
 | `coderm.workbench.editor.resizePaneRight` | Resize pane rightward |
 | `coderm.workbench.modalEditor.open`       | Open modal editor      |
 | `coderm.workbench.modalEditor.close`      | Close modal editor     |
+| `coderm.workbench.openReadme`             | Open the workspace root's README.md, or create a new untitled file if absent |
 
 > [!TIP]
 > **Modal Editor:** While a modal is open and focused, files from Quick Open and editor-targeted terminals open directly inside it. To run a terminal (e.g. `lazygit`) inside the modal, set `terminal.integrated.defaultLocation: "editor"` — panel terminals do not flow into the modal. Set `coderm.modal.captureContent: false` to restore the upstream behavior (closing the modal and redirecting editors to the main area).

src/vs/workbench/contrib/coderm/browser/coderm.contribution.ts

@@ -21,6 +21,7 @@ import './gitWorktreeDefaults.js';
 import './hideTitleBarMoreActions.js';
 import './inactiveOverlay.js';
 import './modalEditorActions.js';
+import './openReadme.js';
 import './preventNewGroupOnFocus.js';
 import './quickOpenIncludeTerminals.js';
 import './quickOpenLocalFiles.js';

src/vs/workbench/contrib/coderm/browser/openReadme.ts

@@ -0,0 +1,73 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+import { localize2 } from '../../../../nls.js';
+import { Action2, registerAction2 } from '../../../../platform/actions/common/actions.js';
+import { Categories } from '../../../../platform/action/common/actionCommonCategories.js';
+import { ServicesAccessor } from '../../../../platform/instantiation/common/instantiation.js';
+import { ICommandService } from '../../../../platform/commands/common/commands.js';
+import { IFileService } from '../../../../platform/files/common/files.js';
+import { IWorkspaceContextService } from '../../../../platform/workspace/common/workspace.js';
+import { URI } from '../../../../base/common/uri.js';
+import { IEditorService } from '../../../services/editor/common/editorService.js';
+import { NEW_UNTITLED_FILE_COMMAND_ID } from '../../files/browser/fileConstants.js';
+
+/**
+ * Action that opens the workspace root's README.md, falling back to a new
+ * untitled file when it is absent.
+ *
+ * Registered as a command-palette action (`coderm.workbench.openReadme`).
+ */
+class OpenReadmeAction extends Action2 {
+	/** Unique command identifier for this action. */
+	static readonly ID = 'coderm.workbench.openReadme';
+
+	constructor() {
+		super({
+			id: OpenReadmeAction.ID,
+			title: localize2('coderm.workbench.openReadme', 'Open README'),
+			f1: true,
+			category: Categories.File,
+		});
+	}
+
+	/**
+	 * Executes the open README action.
+	 *
+	 * Best-effort resolves the first workspace folder's README.md: if present
+	 * it is opened, otherwise the upstream "New Untitled Text File" command is
+	 * invoked.
+	 *
+	 * @param accessor - Service accessor for dependency injection.
+	 */
+	override async run(accessor: ServicesAccessor): Promise<void> {
+		const workspaceContextService = accessor.get(IWorkspaceContextService);
+		const fileService = accessor.get(IFileService);
+		const editorService = accessor.get(IEditorService);
+		const commandService = accessor.get(ICommandService);
+
+		// Constraint: only the first workspace folder is consulted to keep
+		// resolution cheap and predictable; multi-root workspaces do not scan
+		// every folder (decided trade-off: simplicity over coverage).
+		const workspaceRoot = workspaceContextService.getWorkspace().folders[0]?.uri;
+		const readmeUri = workspaceRoot ? URI.joinPath(workspaceRoot, 'README.md') : undefined;
+
+		// Why executeCommand instead of re-implementing: delegating to the real
+		// upstream command means behavior changes (e.g. language/viewType args)
+		// are tracked for free, and the no-workspace / missing-README cases
+		// share a single fallback path.
+		if (!readmeUri || !await fileService.exists(readmeUri)) {
+			await commandService.executeCommand(NEW_UNTITLED_FILE_COMMAND_ID);
+			return;
+		}
+
+		await editorService.openEditor({
+			resource: readmeUri,
+			options: { pinned: true },
+		});
+	}
+}
+
+registerAction2(OpenReadmeAction);