feat(story-1.4): add session-based authentication with login/logout

migrations/002_create_sessions.up.sql

@@ -0,0 +1,21 @@
+-- Migration: 002_create_sessions
+-- Description: Create the sessions table for stateful authentication
+
+CREATE TABLE IF NOT EXISTS sessions (
+    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+    user_id UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    token VARCHAR(64) NOT NULL UNIQUE,
+    expires_at TIMESTAMPTZ NOT NULL,
+    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    user_agent TEXT,
+    ip_address VARCHAR(45)
+);
+
+-- Index for token lookup (authentication)
+CREATE INDEX IF NOT EXISTS idx_sessions_token ON sessions(token);
+
+-- Index for user_id (session cleanup)
+CREATE INDEX IF NOT EXISTS idx_sessions_user_id ON sessions(user_id);
+
+-- Index for expiration cleanup
+CREATE INDEX IF NOT EXISTS idx_sessions_expires_at ON sessions(expires_at);