ci: deploy examples with SAM stack

[zhongkechen]

Summary

• deploy all Python examples through a SAM stack instead of one Lambda at a time
• run cloud example tests once per supported Python version (3.11, 3.12, 3.13, 3.14)
• serialize cloud deployments per Python version with a job concurrency group
• prefix deployed stack/function names with the Python version prefix, for example Py314
• generate the SAM template on the fly from the examples catalog and remove the checked-in template/update workflow
• replace the examples deploy CLI with a SAM packaging build script
• assume the test deployment role from TEST_ROLE_ARN and verify it lands in TEST_ACCOUNT_ID
• use the pre-existing Lambda execution role from TEST_LAMBDA_EXECUTION_ROLE_ARN for all example functions
• pass a full example-to-function map into cloud tests and update docs for stack deployment
• remove the deploy workflow path filter so it runs for every PR targeting main

Testing

• hatch fmt --check
• python3 -m py_compile packages/aws-durable-execution-sdk-python-examples/scripts/generate_sam_template.py packages/aws-durable-execution-sdk-python-examples/scripts/generate_function_name_map.py packages/aws-durable-execution-sdk-python-examples/scripts/build_examples.py packages/aws-durable-execution-sdk-python-examples/test/conftest.py
• hatch run examples:generate-sam-template
• generated-template assertion: 61 functions use LambdaExecutionRoleArn and no DurableFunctionRole resource is present
• python3 packages/aws-durable-execution-sdk-python-examples/scripts/generate_function_name_map.py --function-name-prefix PythonPr517-
• sam validate --template-file packages/aws-durable-execution-sdk-python-examples/template.generated.json --region us-west-2
• sam build --template-file packages/aws-durable-execution-sdk-python-examples/template.generated.json
• git diff --check

Previously also ran:

• hatch run dev-examples:test -k test_hello_world
• hatch run examples:build

Did not run an actual AWS deploy locally.