[Review] Move payload codec, encode, and decode calls to DataConverter helper methods

[macroscope-gtm-bot]

Recreated from temporalio#1305 for Macroscope review.

Original PR: temporalio#1305 by @jmaeagle99
Status: closed (merged)

Recreated using squash merge commit - exact merged state preserved.

Original PR: temporalio#1305

[macroscopeapp]

Move payload codec, encode, and decode calls to DataConverter helpers across worker bridge, client memo/headers, and failure handling

Route activation/completion encode/decode, memo and header processing, and failure payload transforms through DataConverter helper methods, adding effect guards and replacing direct PayloadCodec usage. Core entry points update include temporalio.bridge.worker.decode_activation, temporalio.bridge.worker.encode_completion, and client memo/header helpers.

📍Where to Start

Start at the DataConverter helper implementations in converter.py, then follow their use in worker.py for activation/completion and the client memo/header paths in client.py.

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Macroscope summarized 2c05b46.