e39bc862cc
Significant performance improvements to the 'Loading media...' phase: - Reduced client-server round trips by consolidating the initial handshake (diagnostics + media fetch) into a single backend call: getMediaManagerInitialState. - Implemented batched Google Drive metadata retrieval in GASDriveService using the Advanced Drive API, eliminating per-file property fetching calls. - Switched to HtmlService templates in showMediaManager to pass initial SKU/Title data directly, enabling the UI shell to appear instantly upon opening. - Updated documentation (ARCHITECTURE.md, MEMORY.md) to clarify Webpack global assignment requirements for GAS functions. - Verified with comprehensive updates to unit and integration tests.