feat(15-01): remove users and sessions tables from schema

- Delete users and sessions table definitions from src/db/schema.ts
- Generate Drizzle migration to drop both tables
- Retain apiKeys, oauthClients, oauthCodes, oauthTokens tables

src/db/schema.ts

@@ -100,23 +100,6 @@ export const settings = sqliteTable("settings", {
 	value: text("value").notNull(),
 });
 
-export const users = sqliteTable("users", {
-	id: integer("id").primaryKey({ autoIncrement: true }),
-	username: text("username").notNull().unique(),
-	passwordHash: text("password_hash").notNull(),
-	createdAt: integer("created_at", { mode: "timestamp" })
-		.notNull()
-		.$defaultFn(() => new Date()),
-});
-
-export const sessions = sqliteTable("sessions", {
-	id: text("id").primaryKey(),
-	userId: integer("user_id")
-		.notNull()
-		.references(() => users.id, { onDelete: "cascade" }),
-	expiresAt: integer("expires_at", { mode: "timestamp" }).notNull(),
-});
-
 export const apiKeys = sqliteTable("api_keys", {
 	id: integer("id").primaryKey({ autoIncrement: true }),
 	name: text("name").notNull(),