RGB KVStore Integration

[dcorral]

This PR adds database persistence for RGB-specific data via the KVStoreSync trait, replacing direct filesystem operations with KVStore calls through dependency injection.

Changes

New KVStore Functions (rgb_utils/mod.rs)

Added namespace constants and persistence functions:

pub const RGB_PRIMARY_NS: &str = "rgb";
pub const RGB_CHANNEL_INFO_NS: &str = "channel_info";
pub const RGB_CHANNEL_INFO_PENDING_NS: &str = "channel_info_pending";
pub const RGB_PAYMENT_INFO_INBOUND_NS: &str = "payment_info_inbound";
pub const RGB_PAYMENT_INFO_OUTBOUND_NS: &str = "payment_info_outbound";
pub const RGB_TRANSFER_INFO_NS: &str = "transfer_info";
pub const RGB_CONSIGNMENT_NS: &str = "consignment";

New functions:

• read_rgb_transfer_info / write_rgb_transfer_info
• read_rgb_channel_info / write_rgb_channel_info / remove_rgb_channel_info
• read_rgb_payment_info / write_rgb_payment_info
• read_rgb_consignment / write_rgb_consignment / remove_rgb_consignment
• get_rgb_channel_info_pending
• is_payment_rgb
• filter_first_hops

Dependency Injection

KVStore is now passed through struct fields as Arc<dyn KVStoreSync + Send + Sync>:

• ChannelManager.rgb_kv_store
• ChannelManagerReadArgs.rgb_kv_store
• ChannelContext.rgb_kv_store
• OutboundPayments.rgb_kv_store
• KeysManager.rgb_kv_store
• InMemorySigner.rgb_kv_store

Updated RGB Functions

All RGB functions now receive KVStore directly instead of filesystem paths:

• color_commitment - Reads pending channel info and payment info from KVStore, writes transfer info
• color_htlc - Reads transfer info from KVStore, writes updated transfer info
• color_closing - Reads pending channel info from KVStore, writes transfer info
• is_channel_rgb - Checks KVStore for channel RGB data
• get_rgb_channel_info - Reads from KVStore
• rename_rgb_files - Renames channel info and consignment entries in KVStore
• handle_funding - Writes consignment and channel info to KVStore
• update_rgb_channel_amount - Reads/writes channel info via KVStore

Proxy Key Pattern for HTLC Payments

Payment info uses a proxy key scheme for HTLC tracking:

• Main key: payment_hash (hex)
• Proxy key: {channel_id}_{payment_hash}
• Pending key: {payment_hash}_pending

Design

1. KVStore via dependency injection - Flows through all main structures rather than using a global registry
2. Namespaced storage - All RGB data organized under rgb primary namespace with typed secondary namespaces
3. Structured serialization - RgbInfo, RgbPaymentInfo, and TransferInfo serialized to KVStore

Breaking Changes

The following public functions now require a kv_store parameter instead of filesystem paths:

Function	New Parameter
is_channel_rgb	kv_store: &K where K: KVStoreSync
update_rgb_channel_amount	kv_store: &K where K: KVStoreSync
write_rgb_payment_info_file	kv_store: &K where K: KVStoreSync (also removed ldk_data_dir)
color_htlc	kv_store: &dyn KVStoreSync
color_closing	kv_store: &dyn KVStoreSync
handle_funding	kv_store: &K where K: KVStoreSync

Struct constructors (ChannelManager, KeysManager, InMemorySigner, OutboundPayments) now require an rgb_kv_store parameter.