fix(close): treat re-close of already-closed issue as idempotent success (GH#4025)

[kevglynn]

Summary

Fixes #4025.

bd close <id> returns "issue not found" when re-closing an already-closed issue within the same wall-clock second. The root cause: the UPDATE touches no columns (status already closed, timestamps identical within the same second), so RowsAffected() returns 0 — previously misinterpreted as "row doesn't exist."

Fix

When RowsAffected == 0, query the row's current status in the same transaction:

• If already closed → return success silently (idempotent, no duplicate event)
• If row truly missing → preserve "issue not found" error
• If row exists but in unexpected state → return generic failure

Follows the same idempotent pattern already used in claim.go.

Test plan

• Close an issue, immediately close again → success (no error)
• Close a nonexistent ID → still returns "issue not found"
• No duplicate closed event recorded on re-close
• Scripts doing bd close $id && bd close $id no longer fail

[codecov-commenter]

Codecov Report

❌ Patch coverage is 0% with 11 lines in your changes missing coverage. Please review.
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
internal/storage/issueops/close.go	0.00%	11 Missing ⚠️

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[harry-miller-trimble]

Thanks, @kevglynn! Rebased onto current main (this branch is ~50 commits behind) and added sqlmock tests for the new idempotent-close path in #4199. Your original commit is preserved there with attribution.

Continuing review in #4199; this can be closed in favor of it.

[kevglynn]

Thanks @harry-miller-trimble! The sqlmock tests for the idempotent path are a nice addition.