fix(terminal): support browser clipboard shortcuts

Copy selected terminal output with Ctrl/Cmd+C without sending an interrupt, and route browser paste consistently through the terminal transport.

apps/web/src/components/features/terminal/terminal.test.ts

@@ -4,6 +4,7 @@ import {
 	getTerminalScrollbackLimit,
 	isCurrentWebSocket,
 	shouldRetryWebSocketClose,
+	shouldCopyTerminalSelection,
 } from "./terminal.tsx";
 
 describe("getTerminalScrollbackLimit", () => {
@@ -30,3 +31,29 @@ describe("getTerminalScrollbackLimit", () => {
 		);
 	});
 });
+
+describe("shouldCopyTerminalSelection", () => {
+	it("copies a selected terminal region with Ctrl+C or Cmd+C", () => {
+		expect(
+			shouldCopyTerminalSelection(
+				{ ctrlKey: true, metaKey: false, key: "c" },
+				true,
+			),
+		).toBe(true);
+		expect(
+			shouldCopyTerminalSelection(
+				{ ctrlKey: false, metaKey: true, key: "C" },
+				true,
+			),
+		).toBe(true);
+	});
+
+	it("keeps Ctrl+C as a terminal interrupt without a selection", () => {
+		expect(
+			shouldCopyTerminalSelection(
+				{ ctrlKey: true, metaKey: false, key: "c" },
+				false,
+			),
+		).toBe(false);
+	});
+});