Fix MCP-RES source drift workflow output

[aliengineering-byte]

Summary

• replace the over-escaped Bash command substitution that failed after a successful drift check
• emit the already-generated boolean with jq
• preserve the bounded official-source allowlist and issue behavior

Evidence

• failing workflow: https://github.com/aliengineering-byte/resilireplay/actions/runs/33137408539
• checker result before the shell failure: reviewRequired=false, drift=0, incomplete=0
• local checker: PASS
• Prettier: PASS
• git diff --check: PASS

This hotfix changes no normative standard, schema, vector, validator, release asset, or v0.1 artifact.