fix(page-controller): apply scroll direction to pixels parameter

Two bugs in the scroll direction logic:

1. Vertical scroll with `pixels` ignores the `down` boolean because the
   `??` operator bypasses the direction multiplier when pixels is provided.
   Fix: move the direction multiplier outside the `??` so it applies to
   both the pixels and numPages paths.

2. Horizontal scroll with `pixels` applies direction twice - once in
   PageController.ts and again in actions.ts - causing a double negation
   that reverses the intended direction. Fix: remove the redundant
   direction logic from actions.ts since PageController already signs
   the scroll amount.

Also removes the now-unused `down` and `right` parameters from the
scrollVertically() and scrollHorizontally() action functions.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

packages/page-controller/src/PageController.ts

@@ -321,11 +321,11 @@ export class PageController extends EventTarget {
 
 			this.assertIndexed()
 
-			const scrollAmount = pixels ?? numPages * (down ? 1 : -1) * window.innerHeight
+			const scrollAmount = (pixels ?? numPages * window.innerHeight) * (down ? 1 : -1)
 
 			const element = index !== undefined ? getElementByIndex(this.selectorMap, index) : null
 
-			const message = await scrollVertically(down, scrollAmount, element)
+			const message = await scrollVertically(scrollAmount, element)
 
 			return {
 				success: true,
@@ -356,7 +356,7 @@ export class PageController extends EventTarget {
 
 			const element = index !== undefined ? getElementByIndex(this.selectorMap, index) : null
 
-			const message = await scrollHorizontally(right, scrollAmount, element)
+			const message = await scrollHorizontally(scrollAmount, element)
 
 			return {
 				success: true,

packages/page-controller/src/actions.ts

@@ -231,11 +231,7 @@ export async function scrollIntoViewIfNeeded(element: Element) {
 	}
 }
 
-export async function scrollVertically(
+export async function scrollVertically(scroll_amount: number, element?: HTMLElement | null) {
-	down: boolean,
-	scroll_amount: number,
-	element?: HTMLElement | null
-) {
 	// Element-specific scrolling if element is provided
 	if (element) {
 		const targetElement = element
@@ -359,11 +355,7 @@ export async function scrollVertically(
 	}
 }
 
-export async function scrollHorizontally(
+export async function scrollHorizontally(scroll_amount: number, element?: HTMLElement | null) {
-	right: boolean,
-	scroll_amount: number,
-	element?: HTMLElement | null
-) {
 	// Element-specific scrolling if element is provided
 	if (element) {
 		const targetElement = element
@@ -372,7 +364,7 @@ export async function scrollHorizontally(
 		let scrolledElement: HTMLElement | null = null
 		let scrollDelta = 0
 		let attempts = 0
-		const dx = right ? scroll_amount : -scroll_amount
+		const dx = scroll_amount
 
 		while (currentElement && attempts < 10) {
 			const computedStyle = window.getComputedStyle(currentElement)
@@ -420,7 +412,7 @@ export async function scrollHorizontally(
 
 	// Page-level scrolling (default or fallback)
 
-	const dx = right ? scroll_amount : -scroll_amount
+	const dx = scroll_amount
 	const bigEnough = (el: HTMLElement) => el.clientWidth >= window.innerWidth * 0.5
 	const canScroll = (el: HTMLElement | null) =>
 		el &&