fix(azure): tolerate terminal runs without a gate

[ruby-dlee]

Summary

• allow terminal validation attempts with no awaiting gate to continue into result assembly
• keep real awaiting-gate line detection unchanged
• execute the shipped classifier line under strict shell mode for both empty and present gate cases

Root cause

The gate classifier ran a no-match grep pipeline under set -euo pipefail. A retained run that had already answered its gate completed reattach and status capture, then exited before building its authenticated result because no awaiting gate was expected in the new attempt log.

Evidence

• the live retained attempt reached runtime hydration, reattach, status capture, Git reconciliation, and auth write-back, then published no result
• its exact attempt log had zero awaiting lines and the shipped pipeline returned status 1
• tests/run.sh tests/fm-azure-validation.test.sh
• tests/run.sh tests/fm-behavior-shards.test.sh
• bin/fm-behavior-shards.sh --check 8
• pinned ShellCheck on the changed scripts, shell syntax, Python compile, and diff checks