Add p28 host with CAP-85 support

[dmkozh]

Description

The bulk of the change is the necessary plumbing to adapt Core to the breaking host e2e interface changes (for lazy storage entry decoding).

For CAP-85 itself we don't need any Core changes, so this just has an e2e smoke test.

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

Adds the protocol-28 Soroban host, lazy ledger-entry decoding interface, and CAP-85 executable-reference support.

Changes:

• Adds p28 host dispatch and v2 invocation/rent APIs.
• Refactors Core ledger-input preparation for lazy decoding.
• Adds CAP-85 configuration, smoke coverage, and metadata baselines.

Reviewed changes

Copilot reviewed 22 out of 23 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
.gitmodules	Adds p28 submodule declaration.
Cargo.lock	Updates p28 Rust dependencies.
common.mk	Defines CAP-85 for C++.
configure.ac	Adds CAP-85 conditional.
src/Makefile.am	Enables p28 WIP build.
src/herder/test/TransactionQueueTests.cpp	Removes host-function filtering tests.
src/ledger/LedgerTypeUtils.cpp	Adds p28 rent sizing path.
src/main/main.cpp	Temporarily disables XDR identity checks.
src/rust/Cargo.toml	Upgrades the p28 host dependency.
src/rust/src/bridge.rs	Exposes v2 bridge interfaces.
src/rust/src/dep-trees/p28-expect.txt	Updates expected p28 dependencies.
src/rust/src/lib.rs	Imports v2 ledger metadata.
src/rust/src/soroban_invoke.rs	Dispatches v2 host invocation.
src/rust/src/soroban_module_cache.rs	Dispatches v2 rent sizing.
src/rust/src/soroban_proto_all.rs	Adapts protocol-specific host APIs.
src/rust/src/soroban_proto_any.rs	Implements shared v2 invocation handling.
src/transactions/InvokeHostFunctionOpFrame.cpp	Builds ordered lazy-decoding inputs.
src/transactions/TransactionFrame.cpp	Removes host-function filtering.
src/transactions/test/InvokeHostFunctionTests.cpp	Adds CAP-85 smoke coverage.
src/util/ProtocolVersion.h	Adds p28 activation constants.
test-tx-meta-baseline-next/InvokeHostFunctionTests.json	Registers the new test baseline.