Deprecate TxBody and TxBodyContent in favour of the experimental API

[Jimbo4350]

Context

Deprecates the old-API transaction body surface (the type, its constructor, and direct producers/consumers) so users are pointed at Cardano.Api.Experimental. Internal modules that still use these symbols are annotated with -Wno-deprecations to keep -Werror green; they will be migrated in a follow-up along with the setter family.

Deprecations introduced:

• TxBody (data type), ShelleyTxBody (constructor)
• TxBodyContent (type/constructor)
• createTransactionBody, defaultTxBodyContent
• getTxBody, getTxBodyContent
• BalancedTxBody

The existing pattern-synonym TxBody deprecation message is updated for consistency with the new messages.

How to trust this PR

• Single commit; mechanical addition of {-# DEPRECATED ... #-} pragmas plus -Wno-deprecations OPTIONS_GHC in modules that still consume the deprecated surface internally (so -Werror stays green until the follow-up migrates those callers).
• cabal build cardano-api -j4 is clean against current master.
• Diff is +23/-1 across 10 files; no behavioural change.

Checklist

• Commit sequence broadly makes sense and commits have useful messages
• Self-reviewed the diff
• Changelog fragment added in .changes/ (will add once PR number is assigned)

[Copilot]

Pull request overview

This PR deprecates the legacy transaction body API (TxBody, TxBodyContent, and related helpers) to steer users toward the experimental transaction API, while adding -Wno-deprecations to internal/test modules that still rely on the deprecated surface to keep -Werror builds clean.

Changes:

• Added {-# DEPRECATED #-} pragmas for the legacy Tx body types/constructors and helper functions.
• Added {-# OPTIONS_GHC -Wno-deprecations #-} in internal modules and tests that still use the deprecated API.
• Added a Herald changelog fragment documenting the deprecations.

Reviewed changes

Copilot reviewed 11 out of 11 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
cardano-api/test/cardano-api-test/Test/Cardano/Api/TxBody.hs	Suppress deprecation warnings in tests that still exercise legacy TxBody APIs.
cardano-api/test/cardano-api-test/Test/Cardano/Api/Transaction/Autobalance.hs	Suppress deprecation warnings in autobalance tests still using deprecated symbols.
cardano-api/test/cardano-api-test/Test/Cardano/Api/Experimental.hs	Suppress deprecation warnings in experimental tests that import legacy types during transition.
cardano-api/src/Cardano/Api/Tx/Internal/Sign.hs	Deprecates TxBody, ShelleyTxBody, and getTxBody; suppresses internal deprecation warnings.
cardano-api/src/Cardano/Api/Tx/Internal/Fee.hs	Deprecates BalancedTxBody; suppresses internal deprecation warnings.
cardano-api/src/Cardano/Api/Tx/Internal/Convenience.hs	Suppresses deprecation warnings where legacy balancing/building helpers are still used.
cardano-api/src/Cardano/Api/Tx/Internal/Body.hs	Deprecates TxBodyContent, defaultTxBodyContent, createTransactionBody, getTxBodyContent, and updates the TxBody pattern synonym deprecation message.
cardano-api/src/Cardano/Api/Network/IPC/Internal.hs	Suppresses deprecation warnings due to importing legacy TxBody-related internals.
cardano-api/src/Cardano/Api/Governance/Internal/Poll.hs	Suppresses deprecation warnings due to importing legacy TxBody/metadata internals.
cardano-api/src/Cardano/Api/Experimental/Tx.hs	Suppresses deprecation warnings due to intentional bridging/imports from deprecated legacy internals.
.changes/20260507_cardano_api_deprecate_txbody_txbodycontent.yml	Adds a changelog fragment documenting the deprecations and the temporary warning suppressions.