Add per-user resource quota enforcement across all four dimensions:
max_servers, max_cpu_milli, max_memory_mb, and max_storage_gb.
- Migration 0013: add cached_cpu_milli, cached_memory_mb, cached_storage_mb
columns to servers table for pure-SQL per-owner aggregation
- SeedServer now writes resource cache alongside server row
- QuotaCheck replaces QuotaAvailable at claim time, checking all four caps
against the owning user's cumulative usage
- handlePatchServer checks owner's quota before allowing memory/resource
changes on owned servers; unowned servers skip the gate
- handleInternalClaim mirrors the full quota check
- UpdateServerResources keeps the cache in sync after spec mutations
- Reaper zeros resource cache on ReleaseWorld so released resources
are not counted against a former owner
- quantityToMilli/quantityToMB helpers convert K8s quantities to
quota-comparable integers
19 test packages pass.