feat(auth): add Discord OAuth sign-in and user timezones

Add persistent user and session storage, protected profile requests, and React sign-in controls. Capture and preserve each user's timezone, and load development and production configuration before migrations and server startup.

src/db/schema.ts

@@ -1,2 +1,22 @@
-// Define application tables here with drizzle-orm/sqlite-core.
-export {};
+import { index, integer, sqliteTable, text } from "drizzle-orm/sqlite-core";
+
+export const users = sqliteTable("users", {
+  id: text("id").primaryKey(),
+  discordId: text("discord_id").notNull().unique(),
+  username: text("username").notNull(),
+  globalName: text("global_name"),
+  avatarHash: text("avatar_hash"),
+  timezone: text("timezone").notNull().default("UTC"),
+  createdAt: integer("created_at").notNull(),
+  updatedAt: integer("updated_at").notNull(),
+});
+
+export const sessions = sqliteTable("sessions", {
+  tokenHash: text("token_hash").primaryKey(),
+  userId: text("user_id").notNull().references(() => users.id, { onDelete: "cascade" }),
+  createdAt: integer("created_at").notNull(),
+  expiresAt: integer("expires_at").notNull(),
+}, table => [
+  index("sessions_user_id_idx").on(table.userId),
+  index("sessions_expires_at_idx").on(table.expiresAt),
+]);