Fix pointer address decoder to follow cardano ledger logic

[lisicky]

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[lisicky]

/check

[Copilot]

Pull Request Overview

This PR fixes the pointer address decoder to follow Cardano ledger logic by implementing proper variable-length encoding/decoding and overflow normalization behavior. The changes ensure compatibility with the Haskell implementation by normalizing pointer values to (0,0,0) when any component exceeds its maximum allowed value.

• Implements new variable-length u64 decoder that matches Haskell's decodeVariableLengthWord64 function
• Adds overflow normalization logic that resets pointers to (0,0,0) when values exceed u32::MAX, u16::MAX, or u16::MAX for slot, tx_index, and cert_index respectively
• Refactors Pointer struct into separate module with comprehensive test coverage

Reviewed Changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
rust/src/protocol_types/pointer.rs	New module containing Pointer struct with Cardano-compliant variable-length encoding/decoding
rust/src/protocol_types/address.rs	Removes old Pointer implementation and variable-length nat functions, updates to use new Pointer module
rust/src/protocol_types/numeric/big_num.rs	Adds From implementation for BigNum
rust/src/protocol_types/mod.rs	Exports new pointer module
rust/src/tests/pointer.rs	Comprehensive test suite for pointer functionality
rust/src/tests/mod.rs	Adds pointer test module
rust/src/tests/address.rs	Updates test expectations for overflow normalization behavior

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[lisicky]

/check