Introduce PostgresDeploymentCompatibilityStore with migration 011, in-memory
fallback, deployment endpoints, and Postgres fixture for integration tests.
Update Scheduler repository with connection policy adoption.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Wire AddStartupMigrations so JobEngine converges the orchestrator schema
on fresh database or wiped volumes without manual bootstrap scripts.
Adds StellaOps.Infrastructure.Postgres.Migrations dependency.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>