[codex] support Swift 6.4 coverage report paths

[steipete]

Summary

• find SwiftPM's coverage JSON by its stable codecov/remindctl.json suffix
• accept both legacy lowercase debug and current Swift 6.4 Products/Debug output layouts

Root cause

scripts/check-coverage.sh hardcoded a lowercase debug path component. Swift 6.4's current build system writes the same report under .build/coverage/out/Products/Debug/codecov, so the 90% gate failed after otherwise successful tests.

Validation

• bash -n scripts/check-coverage.sh
• scripts/check-coverage.sh — 92.5% (515/557), 90% minimum
• git diff --check

[clawsweeper]

ClawSweeper status: review started.

I am starting a fresh review of this pull request: [codex] support Swift 6.4 coverage report paths This is item 1/1 in the current shard. Shard 0/1.

This placeholder means the worker is alive and reading the current context. I will edit this same comment with the actual review when the claws are done clicking.

Crustacean status: shell secured, claws on keyboard, evidence pebbles being sorted.