Add db support for workspaces

backend/internal/db/migrations.go

@@ -18,6 +18,53 @@ var migrations = []Migration{
 			settings JSON NOT NULL
 		)`,
 	},
+	{
+		Version: 2,
+		SQL: `
+		-- Create users table
+		CREATE TABLE IF NOT EXISTS users (
+			id INTEGER PRIMARY KEY AUTOINCREMENT,
+			username TEXT NOT NULL UNIQUE,
+			email TEXT NOT NULL UNIQUE,
+			password_hash TEXT NOT NULL,
+			created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
+		);
+
+		-- Create workspaces table
+		CREATE TABLE IF NOT EXISTS workspaces (
+			id INTEGER PRIMARY KEY AUTOINCREMENT,
+			user_id INTEGER NOT NULL,
+			name TEXT NOT NULL,
+			created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+			FOREIGN KEY (user_id) REFERENCES users (id)
+		);
+
+		-- Create workspace_settings table
+		CREATE TABLE IF NOT EXISTS workspace_settings (
+			workspace_id INTEGER PRIMARY KEY,
+			settings JSON NOT NULL,
+			FOREIGN KEY (workspace_id) REFERENCES workspaces (id)
+		);
+
+		-- Migrate existing settings to a default user and workspace
+		INSERT INTO users (username, email, password_hash) 
+		VALUES ('default_user', 'default@example.com', 'placeholder_hash');
+
+		INSERT INTO workspaces (user_id, name, root_path) 
+		SELECT 1, 'Default Workspace'
+		WHERE NOT EXISTS (SELECT 1 FROM workspaces);
+
+		INSERT INTO workspace_settings (workspace_id, settings)
+		SELECT w.id, s.settings
+		FROM workspaces w
+		CROSS JOIN settings s
+		WHERE w.name = 'Default Workspace'
+		  AND NOT EXISTS (SELECT 1 FROM workspace_settings);
+
+		-- Drop the old settings table
+		DROP TABLE IF EXISTS settings;
+		`,
+	},
 }
 
 func (db *DB) Migrate() error {