Add comprehensive documentation for the blocked_issues_cache optimization
that improved GetReadyWork performance from 752ms to 29ms (25x speedup).
Documentation locations:
- blocked_cache.go: Detailed package comment covering architecture,
invalidation strategy, transaction safety, edge cases, and future
optimizations
- ready.go: Enhanced comment at query site explaining the optimization
and maintenance triggers
- ARCHITECTURE.md: New section with diagrams, blocking semantics,
performance characteristics, and testing instructions
Closes bd-1w6i
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Co-Authored-By: Claude <noreply@anthropic.com>
fcd6ca694e