fix: fail orphaned batch parents instead of leaving processing jobs

[chubes4]

Summary

• mark parent batch jobs as failed when batch transient state is missing instead of leaving them in processing
• fail parent batches when final chunk completes but zero child jobs were actually scheduled
• add unit coverage for both failure paths in PipelineBatchSchedulerTest

Why

On events.extrachill.com, parent jobs could remain in processing despite Action Scheduler actions completing. This change adds explicit terminal states for orphaned/empty batch paths so queue state stays truthful and scalable.

Testing

• homeboy test data-machine --skip-lint --path=\"/var/lib/datamachine/workspace/data-machine\" -- --filter \"PipelineBatchSchedulerTest|ToolResultFinderTest\"

[github-actions]

Homeboy Results — data-machine

Tooling versions

• Homeboy CLI: homeboy 0.56.0
• Extension: wordpress from https://github.com/Extra-Chill/homeboy-extensions
• Extension revision: unknown
• Action: Extra-Chill/homeboy-action@v1

ℹ️ PR test scope resolved to full for compatibility with installed Homeboy CLI

✅ lint (changed files only)

• PHPCS: LINT SUMMARY: 4 errors, 9 warnings
• Fixable: 8 | Files with issues: 1 of 1
• PHPStan: PHPSTAN SUMMARY: 133 errors at level 5

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Homeboy Action v1 — homeboy 0.56.0