Add option to generate LCM from tests

[sisuresh]

Description

Resolves #5125

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 an opt-in test runner mode to automatically capture and persist LedgerCloseMeta (LCM) emitted during ledger closes, primarily to support downstream meta consumers and deterministic fixtures.

Changes:

• Introduces --capture-lcm in the test runner, accumulating LCM during closeLedger/closeLedgerOn and writing stream-framed XDR files per leaf Catch2 section/test-case.
• Updates LedgerManagerImpl (tests-only) to retain the most-recent LedgerCloseMeta (with ledger header) for inspection/capture.
• Tags a curated set of tests with [gen-lcm] and fixes several test ledger-close loops to advance from LCL+1 (to align with stricter assertions).

Reviewed changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
src/transactions/test/SorobanTxTestUtils.cpp	Adds logging include and fixes namespace comment.
src/transactions/test/InvokeHostFunctionTests.cpp	Adds [gen-lcm] tags; fixes several loops to close ledgers starting at LCL+1.
src/transactions/test/FrozenLedgerKeysTests.cpp	Adds [gen-lcm] tags to selected tests.
src/test/TxTests.h	Declares global accumulated-LCM helpers for tests.
src/test/TxTests.cpp	Implements accumulated-LCM storage; captures LCM during ledger closes; adds stricter ledger sequence assertion.
src/test/TestUtils.cpp	Appends LCM after Soroban network config upgrades when capture is enabled.
src/test/test.h	Declares isLcmCaptureEnabled() for test helpers to query capture mode.
src/test/test.cpp	Implements --capture-lcm, per-section capture bookkeeping, and file output under test-lcm/.
src/ledger/LedgerManagerImpl.cpp	Moves/stabilizes tests-only mLastLedgerCloseMeta capture and ensures it includes the final ledger header.
docs/software/commands.md	Documents --capture-lcm, expected output layout, and [gen-lcm] usage.

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