apollo_rpc: delete client_transaction conversion impls

[ShahakShama]

Remove all From/TryFrom impls converting RPC transaction types to
apollo_starknet_client::writer::objects::transaction types. These were
only used by the add_*_transaction handlers removed in the previous PR.

Also removes TypedInvokeTransaction and TypedDeployAccountTransaction,
which were only needed as input types for the deleted handlers.

Co-Authored-By: Claude Sonnet 4.6 noreply@anthropic.com

[ShahakShama]

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• apollo_starknet_client: move RetryErrorCode definition to reader module #14279
• apollo_starknet_client: move ClientCreationError definition to reader module #14278
• apollo_starknet_client: move ClientError definition to reader module #14277
• apollo_starknet_client: inline StarknetClient into StarknetFeederGatewayClient #14276
• apollo_starknet_client,apollo_rpc: delete writer module #14275
• apollo_rpc,apollo_node_config,apollo_deployments: remove writer fields from RpcConfig #14274
• apollo_rpc,apollo_state_sync: remove writer_client plumbing from RPC server #14273
• apollo_rpc: delete write_api_result module #14272
• apollo_rpc: delete client_transaction conversion impls #14271 👈 (View in Graphite)
• apollo_rpc: delete write_api_error module #14270
• apollo_rpc: delete addInvokeTransaction, addDeclareTransaction, addDeployAccountTransaction #14269
• apollo_rpc: delete gateway_integration_test #14268
• main

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[cursor]

PR Summary

Low Risk
Pure deletion of unused conversion code with no remaining references in apollo_rpc; no runtime behavior change expected.

Overview
Removes dead conversion code between RPC v0.8 transaction types and apollo_starknet_client::writer::objects::transaction, left over after dropping the add_*_transaction RPC handlers.

In broadcasted_transaction.rs, deletes TryFrom<BroadcastedDeclareTransaction> for declare v1/v2/v3 (including Sierra compression and client ContractClass mapping) and drops unused imports (client_transaction, compress_and_encode, StorageSerdeError).

In transaction.rs, removes all From impls mapping invoke/deploy-account RPC structs and enums into the writer client types, and removes TypedInvokeTransaction and TypedDeployAccountTransaction (typed JSON wrappers that only served those handlers).

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[reviewable-StarkWare]

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