refactor(workbench): drop per-card height and free-form resize

Height was practically unused — most WorkbenchSceneApp rows had
heightPx: undefined and scrolled internally, and the few explicit
values nobody ever revisited were just noise in the sync ledger.
Same goes for pixel-precise drag: users would produce widths like
823px and then never touch them again. Both paths come out in
favour of a fixed set of five width presets (next commit) that
guarantee cards sit on sensible sizes without a decision per card.

- types/workbench-scenes: heightPx removed from WorkbenchSceneApp
- page-carousel/types: heightPx removed from CarouselPage
- stores/workbench-scenes: resizeApp(appId, widthPx) loses its
  height param; patchScene allowlist no longer lists heightPx.
  Existing Dexie rows with heightPx set simply stop being read
  — the field ages out the next time the row is written.
- PageCarousel: placeholder renders width-only; comment updated
- AppPage: heightPx prop + onResize height param gone
- +page.svelte: carouselPages no longer carries heightPx, handler
  signature narrowed to (id, widthPx)

This commit removes the data; the next commit rewires PageShell's
UI so the drag handle is replaced by the five-preset picker.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

apps/mana/apps/web/src/lib/components/page-carousel/PageCarousel.svelte

@@ -119,9 +119,7 @@
 				{:else}
 					<div
 						class="page-placeholder"
-						style="width: {p.widthPx ?? defaultWidth}px;{p.heightPx
-							? ` height: ${p.heightPx}px;`
-							: ''}"
+						style="width: {p.widthPx ?? defaultWidth}px;"
 						aria-hidden="true"
 					></div>
 				{/if}
@@ -179,11 +177,12 @@
 		align-items: center;
 	}
 	/* Sized stand-in for a not-yet-mounted card. Matches the card's
-	   widthPx/heightPx so scroll position and the surrounding flex
-	   layout stay stable while the IntersectionObserver decides which
-	   cards to mount. Falls back to 60vh height when heightPx is
-	   absent (the same minimum the empty state uses), which keeps the
-	   track from collapsing on initial paint. */
+	   widthPx so scroll position and the surrounding flex layout stay
+	   stable while the IntersectionObserver decides which cards to
+	   mount. Height falls back to 60vh (the same minimum the empty
+	   state uses), which keeps the track from collapsing on initial
+	   paint. Card bodies scroll internally — per-card heights were
+	   dropped in favour of a single viewport-height policy. */
 	.page-placeholder {
 		min-height: 60vh;
 		border-radius: 1.25rem;

apps/mana/apps/web/src/lib/components/page-carousel/types.ts

@@ -4,7 +4,6 @@ export interface CarouselPage {
 	id: string;
 	maximized?: boolean;
 	widthPx: number;
-	heightPx?: number;
 	title: string;
 	color: string;
 	icon?: Component;

apps/mana/apps/web/src/lib/components/workbench/AppPage.svelte

@@ -15,11 +15,10 @@
 	interface Props {
 		appId: string;
 		widthPx: number;
-		heightPx?: number;
 		maximized?: boolean;
 		onClose: () => void;
 		onMaximize?: () => void;
-		onResize?: (widthPx: number, heightPx?: number) => void;
+		onResize?: (widthPx: number) => void;
 		onMoveLeft?: () => void;
 		onMoveRight?: () => void;
 		onContextMenu?: (e: MouseEvent) => void;
@@ -28,7 +27,6 @@
 	let {
 		appId,
 		widthPx,
-		heightPx,
 		maximized = false,
 		onClose,
 		onMaximize,
@@ -296,7 +294,6 @@
 	<!-- Base: PageShell with list view (always visible) -->
 	<PageShell
 		{widthPx}
-		{heightPx}
 		{maximized}
 		title={appName}
 		titleHref={`/${appId}`}

apps/mana/apps/web/src/lib/stores/workbench-scenes.svelte.ts

@@ -296,12 +296,8 @@ export const workbenchScenesStore = {
 		);
 	},
 
-	async resizeApp(appId: string, widthPx: number, heightPx?: number) {
-		await patchActiveScene((apps) =>
-			apps.map((a) =>
-				a.appId === appId ? { ...a, widthPx, ...(heightPx !== undefined ? { heightPx } : {}) } : a
-			)
-		);
+	async resizeApp(appId: string, widthPx: number) {
+		await patchActiveScene((apps) => apps.map((a) => (a.appId === appId ? { ...a, widthPx } : a)));
 	},
 
 	async moveAppLeft(appId: string) {

apps/mana/apps/web/src/lib/types/workbench-scenes.ts

@@ -17,8 +17,8 @@ import type { WallpaperConfig } from '@mana/shared-theme';
 export interface WorkbenchSceneApp {
 	appId: string;
 	maximized?: boolean;
+	/** Width preset in pixels. See PAGE_WIDTH_PRESETS for allowed values. */
 	widthPx?: number;
-	heightPx?: number;
 }
 
 /** A user-defined named layout of the workbench. */

apps/mana/apps/web/src/routes/(app)/+page.svelte

@@ -106,7 +106,6 @@
 				id: a.appId,
 				maximized: a.maximized,
 				widthPx: a.widthPx ?? DEFAULT_WIDTH,
-				heightPx: a.heightPx,
 				title: appTitles.get(a.appId) ?? a.appId,
 				color: entry?.color ?? '#6B7280',
 				icon: entry?.icon,
@@ -192,8 +191,8 @@
 	function handleMaximizeApp(id: string) {
 		workbenchScenesStore.toggleMaximizeApp(id);
 	}
-	function handleResize(id: string, widthPx: number, heightPx?: number) {
-		workbenchScenesStore.resizeApp(id, widthPx, heightPx);
+	function handleResize(id: string, widthPx: number) {
+		workbenchScenesStore.resizeApp(id, widthPx);
 	}
 	function handleMoveLeft(id: string) {
 		workbenchScenesStore.moveAppLeft(id);
@@ -329,11 +328,10 @@
 			<AppPage
 				appId={p.id}
 				widthPx={p.widthPx}
-				heightPx={p.heightPx}
 				maximized={p.maximized}
 				onClose={() => handleRemoveApp(p.id)}
 				onMaximize={() => handleMaximizeApp(p.id)}
-				onResize={(w, h) => handleResize(p.id, w, h)}
+				onResize={(w) => handleResize(p.id, w)}
 				onMoveLeft={idx > 0 ? () => handleMoveLeft(p.id) : undefined}
 				onMoveRight={idx < openApps.length - 1 ? () => handleMoveRight(p.id) : undefined}
 				onContextMenu={(e) => handleCardContextMenu(e, p.id, idx)}