fix: recognize tier-cap node-owner rejection reason

[huangminghuang]

Summary

• Label nodeownerreg.reason = 6 as NodeOwnerRejectReason.TierCapReached.
• Preserve the existing rejection values and expose the new label through the existing enum export.

Why

Sysio PR #648 records tier-capacity exhaustion as a soft rejection so node-owner claims cannot roll back envelope consensus. The Tools mirror must recognize the new reason when reporting a rejected claim. This completes the tooling follow-up in WIRE-417.

Validation

• EthereumNodeOwnerNftTool.test.ts: all 5 tests pass with published @wireio/sdk-core@1.0.92.
• The emitted module resolves numeric reason 6 to TierCapReached; repository lint passes.
• The broader cluster-tool typecheck remains blocked by existing string-versus-SlugNameType errors in unchanged call sites. SDK 1.0.93 publication is pending the upstream strict-null fix; the enum change introduces no SDK dependency update.

Companion PRs

• wire-sysio #648: emits the new rejection reason and prevents over-cap claims from creating accounts or stalling epochs. The enum label may merge independently; it does not gate the contract fix.