chore: prepare release 2.0.0

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This PR was created automatically. Merging it will finalize the changelog for 2.0.0

Breaking Changes

• Remove RHP Session endpoints

Support V2 Hardfork

The V2 hardfork is scheduled to modernize Sia's consensus protocol, which has been untouched since Sia's mainnet launch back in 2014, and improve accessibility of the storage network. To ensure a smooth transition from V1, it will be executed in two phases. Additional documentation on upgrading will be released in the near future.

V2 Highlights

• Drastically reduces blockchain size on disk
• Improves UTXO spend policies - including HTLC support for Atomic Swaps
• More efficient contract renewals - reducing lock up requirements for hosts and renters
• Improved transfer speeds - enables hot storage

Phase 1 - Allow Height

• Activation Height: 513400 (March 10th, 2025)
• New Features: V2 transactions, contracts, and RHP4
• V1 Support: Both V1 and V2 will be supported during this phase
• Purpose: This period gives time for integrators to transition from V1 to V2
• Requirements: Users will need to update to support the hardfork before this block height

Phase 2 - Require Height

• Activation Height: 526000 (June 6th, 2025)
• New Features: The consensus database can be trimmed to only store the Merkle proofs
• V1 Support: V1 will be disabled, including RHP2 and RHP3. Only V2 transactions will be accepted
• Requirements: Developers will need to update their apps to support V2 transactions and RHP4 before this block height

Switch to core consensus

Removes the last legacy code from siad. Switching between Mainnet and Testnet can now be done with a CLI flag e.g. --network=zen. This will require hosts to resync the blockchain. Refrain from upgrading if contracts are about to expire.

Features

• Attempt to upgrade existing configs instead of exiting

Add RHP4 support

RHP4 is the next generation of renter-host protocol for the Sia storage network. It dramatically increases performance compared to RHP3, improves contract payouts, reduces collateral lockup, and enables features necessary for light clients. The new protocol will be available and activated starting at block height 513400 (March 10th, 2025).

Refactor Sector Management

Improves sector lookups by 50% on average by removing the sector lock tables and moving reference pruning out of the hot path.

Fixes

• Automate changelog generation
• Move RHP2 and RHP3 settings into the config manager to be consistent with RHP4