fix: restore mobile terminal scrolling

- Retain xterm normal-buffer history on mobile while preserving desktop zero-scrollback behavior\n- Repair ProjectsPage tests for session context and current project list markup\n- Add focused terminal scrollback coverage\n\nOpenSpec: fix-mobile-terminal-scrolling\nQuality gates: npm run typecheck, npm run lint, npm test (89 passed), npm run build

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

@@ -0,0 +1,13 @@
+import { describe, expect, it } from "vitest";
+
+import { getTerminalScrollbackLimit } from "./terminal.tsx";
+
+describe("getTerminalScrollbackLimit", () => {
+	it("retains normal-buffer history for custom mobile swipe scrolling", () => {
+		expect(getTerminalScrollbackLimit(true)).toBe(10_000);
+	});
+
+	it("keeps desktop scrollback disabled to prevent stale-frame wheel scrolling", () => {
+		expect(getTerminalScrollbackLimit(false)).toBe(0);
+	});
+});

apps/web/src/components/features/terminal/terminal.tsx

@@ -53,6 +53,10 @@ const BRACKETED_PASTE_DISABLE_SEQUENCE = [0x1b, 0x5b, 0x3f, 0x32, 0x30, 0x30, 0x
 const BRACKETED_PASTE_CONTROL_TAIL_LENGTH =
 	BRACKETED_PASTE_ENABLE_SEQUENCE.length - 1;
 
+export function getTerminalScrollbackLimit(isMobile: boolean): number {
+	return isMobile ? 10_000 : 0;
+}
+
 function matchesByteSequence(
 	data: Uint8Array,
 	start: number,
@@ -326,14 +330,11 @@ export const TerminalComponent = React.forwardRef<TerminalRef, TerminalProps>(
 				lineHeight: 1.2,
 				letterSpacing: 0,
 				allowTransparency: false,
-				// This terminal only ever hosts full-screen TUI tools (pi-agent,
-				// opencode), which repaint in place in the normal buffer and do not
-				// use the alternate screen or mouse tracking. With scrollback, every
-				// repaint accumulates as history → a viewport scrollbar appears and
-				// the mouse-wheel scrolls through stale frames instead of the app.
-				// scrollback:0 keeps only the live viewport: no bar, no stale-frame
-				// wheel jank. (Scrollbar is also hidden via CSS for belt-and-suspenders.)
-				scrollback: 0,
+				// Desktop tools repaint in place, so retaining their normal buffer
+				// creates stale frames that native wheel scrolling can revisit. Mobile
+				// instead uses its custom touch handler to scroll normal-buffer output,
+				// which requires retained history.
+				scrollback: getTerminalScrollbackLimit(isMobile),
 				ignoreBracketedPasteMode: false,
 				fastScrollSensitivity: 0,
 				scrollSensitivity: 0,