Enforce org connection limits cluster-wide

[EDsCODE]

Summary

• Enforce org connection admission through a cluster-wide FIFO queue and durable lease table, with retries safe for granted requests and request ID reuse races.
• Re-read runtime max connection limits while queued, and keep queued runtime limiter requests lease-backed even when the limit changes to unlimited.
• Drain org stacks before pool shutdown, including active sessions, blocked creates/reconnects, worker-crash cleanup, and lease release ordering.
• Refactor session draining into a dedicated lifecycle helper and move org connection lease logic into a focused configstore file to keep the implementation easier to reason about.

Testing

• just test-controlplane
• just test-configstore-integration
• just test-controlplane-k8s
• git diff --check

Notes

• just lint was run but could not complete locally because golangci-lint is not installed: sh: golangci-lint: command not found.