chore: prepare release 0.9.0

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This PR was created automatically. Merging it will create a new release for 0.9.0

Breaking Changes

Finalize V2 Hardfork Dates

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

Fixes

• Fix rhp4 server not returning ErrNotEnoughFunds when account has insufficient balance