feat: add theme provider and control components for light/dark mode

- Implemented ThemeProvider to manage theme state and preferences.
- Added ThemeControl component for users to switch between system, light, and dark themes.
- Integrated localStorage for theme preference persistence.
- Updated document styles based on theme changes.

test: add tests for permanent deletion of habits and related records

- Created tests to ensure permanent deletion of habits removes all dependent records.
- Verified that deletion requires ownership, authentication, and checks for archived habits.
- Added tests to confirm rollback behavior on deletion failures.

test: add tests for habit palette and progress card functionality

- Implemented tests for habit color progression and theme-based color shading.
- Added tests for progress card calculations and calendar display logic.

feat: define theme types and preferences

- Introduced Theme and ThemePreference types for better type safety.
- Created utility functions for resolving theme based on user preference and system settings.
- Defined theme palettes for light and dark modes to ensure adequate contrast.

src/components/design-system/calendar-model.ts

@@ -1,3 +1,5 @@
+import { habitProgressColor } from "../../lib/habit-palette";
+import type { Theme } from "../../lib/theme";
 export const PROGRESS_SHADES = [
   "#eeeeee",
   "#d8d8d8",
@@ -103,7 +105,7 @@ export function describeDay(day: CalendarDay, unit: string) {
 }
 
 /** Only show shades that the chart's completion targets can produce. */
-export function legendShades(days: CalendarDay[], color = "#111111") {
+export function legendShades(days: CalendarDay[], color = "#111111", theme?: Theme) {
   const levels = new Set<number>();
   for (const target of new Set(days.map((day) => day.target))) {
     if (!Number.isFinite(target) || target <= 0) continue;
@@ -118,7 +120,7 @@ export function legendShades(days: CalendarDay[], color = "#111111") {
     ...[...levels]
       .sort((a, b) => a - b)
       .map((value) =>
-        progressShade({ date: "", value, target: 8, state: "due" }, color),
+        theme ? habitProgressColor(color, (value - 1) / 7, theme) : progressShade({ date: "", value, target: 8, state: "due" }, color),
       ),
   ];
 }