add habit tracking page with grid layout\

\
- Add HabitGrid component with a responsive calendar-style layout\\
- Support variable habit durations with period-based cell rendering\
- Add skeleton loading states for better UX during data fetching
- Add CounterHabitButton component for cells with increment/decrement
  interactions\
- Create HabitCellContextMenu for period-based actions (reset, set values, fail)
- Add HabitCreationForm for creating new habits\
- Add HabitActionMenu component for additional  operations on habits
  (archive, delete, edit)\
- Add SetValueDialog component for editing the value of a cell

src/routes/(app)/habits/HabitCellContextMenu.svelte

@@ -0,0 +1,76 @@
+<script lang="ts">
+	import * as ContextMenu from '$lib/components/ui/context-menu';
+	import { RotateCcw, SquarePen, CircleX } from '@lucide/svelte';
+	import SetValueDialog from './SetValueDialog.svelte';
+	import type { HabitWithCompletions } from '$lib/context/habits.svelte';
+
+	let {
+		habit,
+		cell,
+		children,
+		onResetPeriod,
+		onSetValue,
+		onToggleFailed
+	}: {
+		habit: HabitWithCompletions;
+		cell: {
+			value: number;
+			date: string;
+			span: number;
+			gridColumn: number;
+			isFailed: boolean;
+			isEmpty: boolean;
+			periodDates: string[];
+		};
+		children: import('svelte').Snippet;
+		onResetPeriod: () => Promise<void>;
+		onSetValue: (totalValue: number, dailyValues?: Record<string, number>) => Promise<void>;
+		onToggleFailed: () => Promise<void>;
+	} = $props();
+
+	let showSetValueDialog = $state(false);
+
+	async function handleResetPeriod() {
+		await onResetPeriod();
+	}
+
+	async function handleSetValue(totalValue: number, dailyValues?: Record<string, number>) {
+		await onSetValue(totalValue, dailyValues);
+		showSetValueDialog = false;
+	}
+
+	async function handleToggleFailed() {
+		await onToggleFailed();
+	}
+</script>
+
+<ContextMenu.Root>
+	<ContextMenu.Trigger class="w-full">
+		{@render children()}
+	</ContextMenu.Trigger>
+	<ContextMenu.Content class="w-48">
+		<ContextMenu.Item onclick={handleResetPeriod} class="gap-2">
+			<RotateCcw class="h-4 w-4" />
+			Reset period
+		</ContextMenu.Item>
+		
+		<ContextMenu.Item onclick={() => showSetValueDialog = true} class="gap-2">
+			<SquarePen class="h-4 w-4" />
+			Set value...
+		</ContextMenu.Item>
+		
+		<ContextMenu.Separator />
+		
+		<ContextMenu.Item onclick={handleToggleFailed} class="gap-2">
+			<CircleX class="h-4 w-4" />
+			{cell.isFailed ? 'Mark as unfailed' : 'Mark as failed'}
+		</ContextMenu.Item>
+	</ContextMenu.Content>
+</ContextMenu.Root>
+
+<SetValueDialog
+	bind:open={showSetValueDialog}
+	{habit}
+	{cell}
+	onSetValue={handleSetValue}
+/>