impl(bigquery): add default job retry policies

[alvarowolfx]

Towards #6218 #5844

[gemini-code-assist]

Code Review

This pull request introduces a new retry policy module (retry_policy.rs) for BigQuery, defining the RetryableErrors policy and helper functions to map BigQuery error reasons to gRPC status codes. Feedback points out a logic issue in query_job_failed_to_gax_error where permanent errors could be incorrectly mapped to a retryable Code::Unavailable status, potentially causing unnecessary retries. A code suggestion is provided to prioritize retryable errors and fall back to a non-retryable code if none are found.

[codecov]

Codecov Report

❌ Patch coverage is 93.67816% with 11 lines in your changes missing coverage. Please review.
✅ Project coverage is 96.06%. Comparing base (0dac6ea) to head (1089ab4).

Files with missing lines	Patch %	Lines
src/bigquery/src/retry_policy.rs	93.67%	11 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #6233      +/-   ##
==========================================
- Coverage   96.07%   96.06%   -0.01%     
==========================================
  Files         275      276       +1     
  Lines       68829    69003     +174     
==========================================
+ Hits        66126    66289     +163     
- Misses       2703     2714      +11     

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[alvarowolfx]

/gemini review

[gemini-code-assist]

Code Review

This pull request introduces a retry policy for BigQuery, defining retry strategies for both RPC and job-level execution. The review feedback identifies several critical issues: a private-in-public visibility mismatch for RetryableErrors, a type mismatch and logical bug in is_retryable_errors (which should use .all() instead of .any() to avoid retrying permanent failures), a test failure in test_job_attempt_limit due to a mismatched attempt limit, and an outdated assertion in test_is_retryable_errors.

[alvarowolfx]

/gemini review

[gemini-code-assist]

Code Review

This pull request introduces retry and backoff policies for BigQuery, including RetryableErrors for RPC retries and RetryableJobErrors for job-level retries. Feedback suggests updating the RetryableErrors policy to check state.idempotent before retrying to prevent unsafe retries on non-idempotent requests, and updating the corresponding unit tests to verify both idempotent and non-idempotent retry behaviors.