feat: Adds autobuild trigger workflow to avoid the auto-disabling on build loop job

[daghaian]

What changed

The Build Loop workflow was being automatically disabled by GitHub after each run (manual or scheduled), preventing subsequent scheduled builds from firing. The root cause is a known GitHub Actions behavior where workflows with a schedule trigger can be auto-disabled under certain conditions.

Why

Scheduled builds were silently failing to run, which breaks the expected automated build cadence.

Solution

• Removed the schedule trigger from the Build Loop workflow
• Introduced a new trigger_build workflow that owns the schedule, re-enables the Build Loop workflow before each run, and then dispatches it via workflow_dispatch

This sidesteps GitHub's auto-disable behavior by keeping the scheduled entry point in a separate, lightweight workflow that re-activates the primary one before triggering it.

Testing

• Manually triggered trigger_build and confirmed it re-enabled and dispatched Build Loop successfully
• Verified scheduled runs now fire as expected

Review notes

The logic change is isolated to workflow files only — no app code is affected. The main thing worth validating is that the workflow_dispatch + re-enable sequence in trigger_build is robust across the expected trigger scenarios (scheduled, manual).