Docs/migration 1x to 2x

[ayushiahjolia]

Issue #, if available: N/A

Description of changes:
Migration guide for python v2

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[github-actions]

Codex AI review

Found three migration-guide issues: unavailable APIs, a crashing callback example, and replay-unsafe logging. Documentation snippets lack automated validation.

Reviewed commit 162361bd075ac0b1ad3f1ebfaad8191a3c901d14. Workflow run

[github-actions]

Claude AI review

Documentation-only PR: a 1.x→2.x migration guide plus a WaitForConditionConfig docstring addition. The base branch already carries the 2.x API surface, so I verified each concrete claim against packages/aws-durable-execution-sdk-python/src/. Most claims are accurate (typed DurableOperationError hierarchy, RetryableSerDesError/SerDesError exports, WaitForConditionDecision.continue_waiting/stop_polling, BatchResult.throw_if_error() raising ChildContextError, ChildConfig.serdes, removal of InvokeConfig.timeout*, CompletionConfig.all_completed() tolerating all failures). Two claims are wrong against the source and would break copy-pasted code:

• docs/migration-1.x-to-2.x.md:112-147 — "Custom Completion Predicate" documents a non-existent API. CompletionConfig (config.py:102) has no should_complete field, and none of complete_batch, continue_batch, CompletionStatus, CompletionDecision, CompletionOutcome, CompletionItemStatus, or CUSTOM_COMPLETION_* exist anywhere in the repo. The documented import raises ImportError and the constructor call raises TypeError.
• docs/migration-1.x-to-2.x.md:82-83 — e.callback_id is not a real attribute. No CallbackError raise site sets it and the base DurableOperationError.__init__ doesn't define it, so the example raises AttributeError.

Per AGENTS.md ("when the developer guide and the source disagree, trust the source and report the discrepancy"), both are reported below. No test risk applies to a docs change, but the guide should not ship examples that fail on execution.

Reviewed commit 162361bd075ac0b1ad3f1ebfaad8191a3c901d14. Workflow run