feat: replace placeholder auth with db hash

migrations/001_add_users_table.sql

@@ -0,0 +1,22 @@
+-- Users table for authentication
+CREATE TABLE users (
+    id BINARY(16) NOT NULL PRIMARY KEY,
+    username VARCHAR(50) NOT NULL UNIQUE,
+    password_hash VARCHAR(255) NOT NULL,
+    email VARCHAR(255),
+    created_at DATETIME(6) NOT NULL DEFAULT CURRENT_TIMESTAMP(6),
+    updated_at DATETIME(6) NOT NULL DEFAULT CURRENT_TIMESTAMP(6) ON UPDATE CURRENT_TIMESTAMP(6)
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;
+
+-- Create index on username for faster lookups
+CREATE INDEX idx_username ON users(username);
+
+-- Insert default admin user (password: password)
+-- bcrypt hash of "password"
+INSERT INTO users (id, username, password_hash, email)
+VALUES (
+    UUID_TO_BIN(UUID()),
+    'admin',
+    '$2a$10$N9qo8uLOickgx2ZMRZoMyeIjZAgcfl7p92ldGxad68LJZdL17lhWy',
+    'admin@example.com'
+);