Add SQLite database support and user management functionality

migrations/001_create_users_table.sql

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+-- Create the users table
+CREATE TABLE IF NOT EXISTS users (
+    id INTEGER PRIMARY KEY AUTOINCREMENT, -- Unique ID for each user
+    username TEXT NOT NULL UNIQUE,       -- Username, must be unique
+    password_hash TEXT NOT NULL         -- Hashed password for security
+);
+
+-- Create an index on the username and email columns for faster lookups
+CREATE INDEX IF NOT EXISTS idx_users_username ON users (username);