docs(sdk): add exception errors page

[leandrodamascena]

closes #165

Description of changes:

This PR adds docs/advanced/error-handling.md documentation for error handling in durable functions. The guide explains exception types (DurableExecutionsError, InvocationError, ValidationError), AWS-compliant error response formats, and HTTP status code mappings. It covers retry strategies for transient failures, error propagation through operations, and troubleshooting guidance for common scenarios. The testing section shows how to assert on error conditions with test examples.

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[yaythomas]

this does retry from inside a step

[yaythomas]

    retryable_errors: list[str | re.Pattern] = field(
        default_factory=lambda: [re.compile(r".*")]
    )
    retryable_error_types: list[type[Exception]] = field(default_factory=list)

we might want to revisit this logic:

        # Check if error is retryable based on error message
        is_retryable_error_message = any(
            pattern.search(str(error))
            if isinstance(pattern, re.Pattern)
            else pattern in str(error)
            for pattern in config.retryable_errors
        )

        # Check if error is retryable based on error type
        is_retryable_error_type = any(
            isinstance(error, error_type) for error_type in config.retryable_error_types
        )

        if not is_retryable_error_message and not is_retryable_error_type:
            return RetryDecision.no_retry()

if e.g you only want to retry ErrorX and you set

RetryStrategyConfig(retryable_error_types = [ErrorX])

it will still retry basically ALL errors because retryable_errors defaults to a permissive regex - this looks counterintuitive to me.

@ParidelPooya + @PartiallyUntyped

[leandrodamascena]

Hey @yaythomas the PR to fix this is merged. Do you have any additional feedback?