fix(coding-agent): adjusted status-line session accent handling for border gaps

- Status-line rendering now treats `statusLine.sessionAccent` as disabled only when explicitly set to false.
- Updated status-line overflow tests to assert gap colors use session accent when enabled and theme border when disabled.
- Test teardown now restores `WSL_INTEROP` and `WSL_DISTRO_NAME` environment variables after mutation.

packages/coding-agent/src/modes/interactive-mode.ts

@@ -644,10 +644,8 @@ export class InteractiveMode implements InteractiveModeContext {
 		} else if (this.isPythonMode) {
 			this.editor.borderColor = theme.getPythonModeBorderColor();
 		} else {
-			const sessionName =
-				!isSettingsInitialized() || settings.get("statusLine.sessionAccent")
-					? this.sessionManager.getSessionName()
-					: undefined;
+			const accentEnabled = !isSettingsInitialized() || settings.get("statusLine.sessionAccent") !== false;
+			const sessionName = accentEnabled ? this.sessionManager.getSessionName() : undefined;
 			const hex = sessionName ? getSessionAccentHex(sessionName) : undefined;
 			const ansi = getSessionAccentAnsi(hex);
 			if (ansi) {

packages/coding-agent/test/status-line-overflow.test.ts

@@ -10,6 +10,7 @@ import { StatusLineComponent } from "../src/modes/components/status-line";
 import type { SegmentContext } from "../src/modes/components/status-line/segments";
 import { renderSegment } from "../src/modes/components/status-line/segments";
 import { initTheme, theme } from "../src/modes/theme/theme";
+import { getSessionAccentAnsi, getSessionAccentHex } from "../src/utils/session-color";
 
 const originalProjectDir = getProjectDir();
 
@@ -87,19 +88,35 @@ function createStatusLineSession(sessionName: string) {
 }
 
 describe("status line session accent", () => {
-	it("uses theme border color for the gap when session accent is disabled", () => {
+	function buildComponent(sessionAccent: boolean) {
 		const component = new StatusLineComponent(createStatusLineSession("Named session"));
 		component.updateSettings({
 			preset: "custom",
 			leftSegments: ["pi"],
 			rightSegments: ["session_name"],
 			separator: "powerline-thin",
-			sessionAccent: false,
+			sessionAccent,
 		});
+		return component;
+	}
 
-		const border = component.getTopBorder(80).content;
+	const accentAnsi = getSessionAccentAnsi(getSessionAccentHex("Named session"));
+
+	it("paints the gap with the session accent when enabled", () => {
+		expect(accentAnsi).toBeDefined();
+		const border = buildComponent(true).getTopBorder(80).content;
+		expect(border).toContain(`${accentAnsi}${theme.boxRound.horizontal}`);
+	});
+
+	it("paints the gap with the border color and omits the session accent when disabled", () => {
+		expect(accentAnsi).toBeDefined();
+		const border = buildComponent(false).getTopBorder(80).content;
+		// Positive: gap is rendered with the theme border color.
 		expect(border).toContain(`${theme.getFgAnsi("border")}${theme.boxRound.horizontal}`);
-		expect(border).toContain("Named session");
+		// Negative: the gap-painting pattern (accent ANSI directly followed by a horizontal
+		// glyph) must not appear. The session_name segment may still emit the accent ANSI
+		// for its own text — we only care that the gap is not accent-painted.
+		expect(border).not.toContain(`${accentAnsi}${theme.boxRound.horizontal}`);
 	});
 });
 

packages/tui/test/terminal-appearance.test.ts

@@ -5,6 +5,8 @@ const stdinIsTtyDescriptor = Object.getOwnPropertyDescriptor(process.stdin, "isT
 const stdoutIsTtyDescriptor = Object.getOwnPropertyDescriptor(process.stdout, "isTTY");
 const processPlatformDescriptor = Object.getOwnPropertyDescriptor(process, "platform");
 const stdinSetRawModeDescriptor = Object.getOwnPropertyDescriptor(process.stdin, "setRawMode");
+const originalWslDistroName = Bun.env.WSL_DISTRO_NAME;
+const originalWslInterop = Bun.env.WSL_INTEROP;
 
 function restoreProperty(target: object, key: string, descriptor: PropertyDescriptor | undefined): void {
 	if (descriptor) {
@@ -14,6 +16,14 @@ function restoreProperty(target: object, key: string, descriptor: PropertyDescri
 	delete (target as Record<string, unknown>)[key];
 }
 
+function restoreEnv(key: string, original: string | undefined): void {
+	if (original === undefined) {
+		delete Bun.env[key];
+		return;
+	}
+	Bun.env[key] = original;
+}
+
 describe("ProcessTerminal OSC 11 appearance detection", () => {
 	beforeEach(() => {
 		Object.defineProperty(process.stdin, "isTTY", { value: true, configurable: true });
@@ -28,8 +38,8 @@ describe("ProcessTerminal OSC 11 appearance detection", () => {
 		restoreProperty(process.stdout, "isTTY", stdoutIsTtyDescriptor);
 		restoreProperty(process.stdin, "setRawMode", stdinSetRawModeDescriptor);
 		restoreProperty(process, "platform", processPlatformDescriptor);
-		delete Bun.env.WSL_INTEROP;
-		delete Bun.env.WSL_DISTRO_NAME;
+		restoreEnv("WSL_INTEROP", originalWslInterop);
+		restoreEnv("WSL_DISTRO_NAME", originalWslDistroName);
 	});
 
 	function setupTerminal() {