feat: implement incremental card caching to the server per set to prevent payload size limits.

docs/development/CENTRAL.md

@@ -32,3 +32,4 @@
 - [Peasant Algorithm Implementation](./devlog/2025-12-16-225700_peasant_algorithm.md): Completed. Implemented Peasant-specific pack generation rules including slot logic for commons, uncommons, lands, and wildcards.
 - [Multi-Expansion Selection](./devlog/2025-12-16-230500_multi_expansion_selection.md): Completed. Implemented searchable multi-select interface for "From Expansion" pack generation, allowing mixed-set drafts.
 - [Game Type Filter](./devlog/2025-12-16-231000_game_type_filter.md): Completed. Added Paper/Digital filter to the expansion selection list.
+- [Incremental Caching](./devlog/2025-12-16-233000_incremental_caching.md): Completed. Refactored data fetching to cache cards to the server incrementally per set, preventing PayloadTooLarge errors.

docs/development/devlog/2025-12-16-233000_incremental_caching.md

@@ -0,0 +1,13 @@
+# Incremental Data Caching
+
+## Objective
+Enable caching of card data to the server incrementally per set when multiple sets are selected, rather than sending a single massive payload at the end. avoiding `PayloadTooLargeError`.
+
+## Implementation Details
+1.  **Helper Function**: Created `cacheCardsToServer` helper within `fetchAndParse` to handle server communication for a chunk of cards.
+2.  **Incremental Loop**: Modified the set fetching loop to call `cacheCardsToServer` immediately after receiving data for each set.
+3.  **UI Feedback**: Updated progress text to clearly indicate when the system is "Caching [Set Name]..." to the server.
+4.  **Error Handling**: Added try/catch within the caching helper to prevent a single cache failure from aborting the entire fetch process (logs error to console).
+
+## Status
+Completed. Large multi-set fetches should now be robust against body size limits.