Remove cosmosExporterReadinessProbePort validator branch once sei-config gRPC parity propagates

[bdchatham]

Problem

internal/noderesource/noderesource.go has a cosmosExporterReadinessProbePort helper (added in PR #276) that returns Tendermint RPC :26657 for validators and gRPC :9090 for every other mode. This existed to mask the K8s-only divergence where validators had gRPC disabled — once sei-protocol/sei-config#19 lands and propagates, the divergence is gone and the helper becomes dead code.

Impact

The branch is harmless once propagation completes (every mode lands on the same probe target), but stale conditional logic is a maintenance hazard. It also costs anyone reading the file the cognitive load of figuring out why validators are special when they no longer are.

Relevant experts

• kubernetes-specialist (flagged this in the sei-config#19 review)

Acceptance criteria

• feat: enable gRPC on validator mode (parity with sei-infra canonical) sei-config#19 merged and tagged
• seictl bumped to consume new sei-config
• SEI_SIDECAR_IMAGE bumped in platform overlays for harbor + dev + prod
• All validator pods in the fleet cycled (config-apply re-runs on Init/NodeUpdate, not on env-var change — so manual kubectl delete pod per validator may be needed for the ~10-node internal fleet)
• cosmosExporterReadinessProbePort helper removed
• buildCosmosExporterContainer uses :9090 uniformly
• Test fixtures asserting the validator branch in noderesource_test.go updated

Out of scope

• The cosmos-exporter bash wait wrapper for the wait-on-:9090 entrypoint — that's tracked separately. The probe branch removal is independent of the wrapper work; can ship before or after.

References

• feat: enable gRPC on validator mode (parity with sei-infra canonical) sei-config#19 — the change that makes the branch obsolete
• PR fix(noderesource): mode-conditional startup probe for cosmos-exporter #276 — added the mode-conditional helper
• PR fix(noderesource): convert cosmos-exporter probe to ReadinessProbe #280 — converted the failing StartupProbe to a ReadinessProbe