* refactor(github-client): reorganize client into lifecycle folders
* refactor(github-client): extract PR refresh data and outcome assembly
Separate the derived data calculation and outcome assembly logic from
branch-lookup-resolution into dedicated modules for better separation of
concerns. Modernize type import syntax and format exports consistently.
* refactor(github-client): improve error handling and resilience
Defensive GraphQL parsing prevents partial responses from breaking REST fallbacks.
Cache failures now use shorter TTLs for faster recovery. PR operations have
dedicated error classification. GraphQL mutations track rate limit usage to prevent
quota exhaustion. Data validation improved to reject spurious values.
* Extract check rerun error classification with operation context
Create classifyRerunChecksError() to provide operation-specific error
messages when check reruns fail. This replaces generic GitHub error
copy with context appropriate to what the user attempted (rerun
checks). Follows the pattern of classifyListPrsError and improves
error handling by delegating extraction to extractExecError.
* Make check-rerun not-found error message resource-neutral
Error handling for failed check reruns now covers both workflow-run
reruns and standalone check-run rerequests. Tests verify the neutral
message works for both scenarios.