refactor: optimize agent mode

[pigri]

• Replaced MOATFirewall with SYNAPSEFirewall for consistency.
• Improved efficiency by using Arc clones in access rules initialization.
• Added skip_waf_update parameter to apply_rules_from_global to control WAF updates in agent mode.
• Enhanced logging and comments for clarity on agent mode behavior.
• Introduced an expression interner for WAF rules to minimize memory usage.
• Updated global configuration handling to use Arc for efficient sharing.
• Adjusted various components to support agent mode optimizations.
• Added NftablesFirewall struct and associated methods for managing IP bans and notices.
• Integrated nftables as a fallback when BPF/XDP is not available.
• Updated application logic to initialize and apply access rules using nftables.
• Modified configuration to support nftables integration in worker and app state.
• Added necessary dependencies in Cargo.toml and Cargo.lock.
• Introduced a new struct for TCP fingerprint recording to accommodate BPF's argument limits.
• Reduced maximum option length for TCP fingerprints from 40 to 16 to minimize instruction count.
• Removed unused fragmentation checks and the unique fingerprints increment function.
• Updated fingerprint recording functions for both IPv4 and IPv6 to utilize the new struct.