Add p26 module and update cost types

[sisuresh]

Description

1. Adds a p26 module for vnext.
2. Reduce costs due to arkworks library upgrade.

Checklist

• Reviewed the contributing document
• Rebased on top of master (no merge commits)
• Ran clang-format v8.0.0 (via make format or the Visual Studio extension)
• Compiles
• Ran all tests
• If change impacts performance, include supporting evidence per the performance document

[Copilot]

Pull request overview

This PR introduces support for protocol version 26 (P26) and updates cryptographic cost parameters due to improvements in the underlying arkworks library.

Changes:

• Added P26 module infrastructure with corresponding Rust dependencies and build configurations
• Updated CPU and memory cost parameters for BLS12-381 and BN254 cryptographic operations to reflect reduced costs from arkworks library optimizations
• Regenerated test data files for protocol 26 to reflect the cost changes

Reviewed changes

Copilot reviewed 16 out of 17 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
src/util/ProtocolVersion.h	Adds V_26 enum value to the ProtocolVersion enumeration
src/testdata/ledger-close-meta-v2-protocol-26.json	Updates test data with new hash values and fee amounts reflecting reduced costs
src/testdata/ledger-close-meta-v2-protocol-26-soroban.json	Updates Soroban test data with revised transaction costs and account balances
src/testdata/ledger-close-meta-enable-classic-events-v2-protocol-26.json	Updates classic events test data with new costs and hash values
src/testdata/ledger-close-meta-enable-classic-events-v2-protocol-26-soroban.json	Updates Soroban classic events test data with revised fees and addresses
src/rust/src/soroban_proto_all.rs	Adds P26 module with feature gating and protocol dispatch logic
src/rust/src/soroban_module_cache.rs	Adds P26 cache handling to module cache operations
src/rust/src/dep-trees/p26-expect.txt	Adds dependency tree for P26 soroban-env-host
src/rust/soroban/p26	Adds submodule reference for P26 soroban environment
src/rust/Cargo.toml	Adds P26 dependencies and updates quorum analyzer revision
src/ledger/NetworkConfig.h	Declares updateCostTypesForV26 function
src/ledger/NetworkConfig.cpp	Implements V26 cost parameter updates for CPU and memory
src/herder/test/UpgradesTests.cpp	Adds test case verifying V26 upgrade and cost parameter updates
src/herder/Upgrades.cpp	Adds V26 upgrade logic to apply cost parameter updates
src/Makefile.am	Adds P26 to WIP_SOROBAN_PROTOCOL
.gitmodules	Adds P26 submodule configuration