Remove dead store-and-forward and message aggregation code (#438)

- Remove completely unused message aggregation system (100% dead code)
- Remove broken store-and-forward implementation that only worked for relayed messages to offline favorites
- Update documentation to reflect actual functionality
- Net reduction of 312 lines of unmaintained code

Co-authored-by: jack <jackjackbits@users.noreply.github.com>

README.md

@@ -22,7 +22,6 @@ This project is released into the public domain. See the [LICENSE](LICENSE) file
 - **Decentralized Mesh Network**: Automatic peer discovery and multi-hop message relay over Bluetooth LE
 - **Privacy First**: No accounts, no phone numbers, no persistent identifiers
 - **Private Message End-to-End Encryption**: [Noise Protocol](http://noiseprotocol.org)
-- **Store & Forward**: Messages cached for offline peers and delivered when they reconnect
 - **IRC-Style Commands**: Familiar `/slap`, `/msg`, `/who` style interface
 - **Universal App**: Native support for iOS and macOS
 - **Emergency Wipe**: Triple-tap to instantly clear all data
@@ -41,7 +40,6 @@ bitchat uses an efficient binary protocol optimized for Bluetooth LE:
 ### Mesh Networking
 - Each device acts as both client and peripheral
 - Automatic peer discovery and connection management
-- Store-and-forward for offline message delivery
 - Adaptive duty cycling for battery optimization
 
 For detailed protocol documentation, see the [Technical Whitepaper](WHITEPAPER.md).