Bind Better Auth sessions to devices

cloudflare/migrations/0007_better_auth_session_device_context.sql

@@ -0,0 +1,11 @@
+CREATE TABLE IF NOT EXISTS better_auth_session_device_context (
+  session_id TEXT NOT NULL PRIMARY KEY,
+  user_id TEXT NOT NULL,
+  device_id TEXT NOT NULL,
+  updated_at INTEGER NOT NULL,
+  FOREIGN KEY (session_id) REFERENCES better_auth_session (id) ON DELETE CASCADE,
+  FOREIGN KEY (user_id, device_id) REFERENCES user_devices (user_id, device_id) ON DELETE CASCADE
+);
+
+CREATE INDEX IF NOT EXISTS idx_better_auth_session_device_context_user_device
+  ON better_auth_session_device_context (user_id, device_id);