[Serve] Add unit tests for NodePortManager (#61491)
Why
NodePortManager handles per-node port allocation for direct ingress
replicas but has zero unit test coverage in OSS. Any regression in
allocation, release, or cleanup logic would go undetected until
integration tests or production.
What
Add test_node_port_manager.py covering:

HTTP/gRPC port allocation and release
Port reuse after release
Port blocking (post-release exclusion)
Re-allocation of an already-allocated replica (idempotency)
Cleanup/pruning of inactive replicas and stale node managers
Port exhaustion (NoAvailablePortError)
Invalid port release (wrong port number)
Concurrent allocation within a single node
Mixed-protocol allocation for the same replica
Blocked port persistence across allocation cycles
get_port error path for unallocated replicas

All tests use monkeypatched port ranges (5 ports each for HTTP/gRPC)
to keep execution fast and deterministic.
Test plan

pytest python/ray/serve/tests/unit/test_node_port_manager.py -v —
11/11 passed locally

Signed-off-by: Seiji Eicher seiji@anyscale.com