feat: add Home page with user dashboard and habit tracking features

- Implemented Home component with user authentication and loading states.
- Created Welcome component for unauthenticated users with a sign-in option.
- Developed Dashboard component to display user's habits and progress.
- Added functionality for habit management, including adding, updating, and deleting habits.
- Integrated HabitChart and HabitHistory components for visual representation of habits.
- Introduced sharing functionality for progress via Discord integration.

feat: establish Discord sharing configuration and routes

- Added DiscordSharingConfig type and readDiscordSharingConfig function for environment variable management.
- Created sharing contracts for input validation and data structure.
- Implemented sharing routes for previewing and sending progress images to Discord.
- Added tests for sharing routes to ensure authentication and proper error handling.

src/db/schema.ts

@@ -21,6 +21,15 @@ export const sessions = sqliteTable("sessions", {
   index("sessions_expires_at_idx").on(table.expiresAt),
 ]);
 
+export const discordDeliveries = sqliteTable("discord_deliveries", {
+  id: text("id").primaryKey(),
+  userId: text("user_id").notNull().references(() => users.id, { onDelete: "cascade" }),
+  imageHash: text("image_hash").notNull(),
+  status: text("status").notNull(),
+  messageUrl: text("message_url"),
+  createdAt: integer("created_at").notNull(),
+});
+
 // Revisions are append-only, including multiple edits on the same local date.
 export const habits = sqliteTable('habits', {
   id: text('id').primaryKey(), userId: text('user_id').notNull().references(() => users.id),