feat: rewrite, fix and improve the sync architecture (#411)

Modular, parallel, manager-based sync architecture. Each sync concern (`BlockHeadersManager`, `FilterHeadersManager`, `FiltersManager`, `BlocksManager`, `MasternodesManager`, `ChainLockManager`, `InstantSendManager`) has its own manager implementing a common `SyncManager` trait while the `SyncCoordinator` orchestrates them and coordinates the communication between them through a `SyncEvent` system.

Progress reporting is streamlined with each manager reporting its own progress through a unified SyncProgress system which updates the subscribers for every change in progress. Event handling follows the same pattern, with a consistent event model across sync, wallet, and network layers. The FFI can now subscribe to all events from sync progress, wallet, and network.

Filter sync got a lot of fixes and now processes filters and blocks in ordered batches. When gap limit maintenance generates new addresses a rescan is triggered automatically to pick up any transactions that match the new addresses.

Post sync is working stable now too, i was constantly running this branch in the last couple weeks monitoring things and didnt run into any more issues by now.

Author: xdustinface

dash-spv-ffi/FFI_API.md

@@ -336,7 +336,7 @@ int32_t dash_spv_ffi_client_update_config(struct FFIDashSpvClient *client,
  * 0 on success, error code on failure
  */
 
-int32_t dash_spv_ffi_client_sync_to_tip(struct FFIDashSpvClient *client,
+int32_t dash_spv_ffi_client_start_sync(struct FFIDashSpvClient *client,
                                         void (*completion_callback)(bool, const char*, void*),
                                         void *user_data)
 ;
@@ -382,7 +382,7 @@ int32_t dash_spv_ffi_client_sync_to_tip(struct FFIDashSpvClient *client,
  * 0 on success, error code on failure
  */
 
-int32_t dash_spv_ffi_client_sync_to_tip_with_progress(struct FFIDashSpvClient *client,
+int32_t dash_spv_ffi_client_start_sync_with_progress(struct FFIDashSpvClient *client,
                                                       void (*progress_callback)(const struct FFIDetailedSyncProgress*,
                                                                                 void*),
                                                       void (*completion_callback)(bool,