Replace unmaintained ecip_validator gem with local validator

[IstoraMandiri]

Summary

The external ecip_validator gem used in CI does not recognize "WIP" as a valid ECIP status, despite ECIP-1000 explicitly permitting it. This causes validation failures for legitimate work-in-progress proposals.

Problem

The CI pipeline uses an external Ruby gem (ecip_validator) to validate ECIP metadata. This gem:

1. Does not support WIP status - Rejects ECIPs with status: WIP even though ECIP-1000 states: "Draft ECIPs which may be in a very early stage may be entered as WIP ECIPs, which means they are a work in progress."

2. Is unmaintained - The upstream gem is no longer actively maintained, making it impossible to request fixes or updates.

3. Drifts from ECIP standards - As ECIP-1000 evolves, the external validator falls out of sync with the actual rules.

Current Workaround

Prefixing Draft ECIPs with WIP -- see https://ecips.ethereumclassic.org/ECIPs/ecip-1107

Proposed Fix

Replace the external ecip_validator gem with a locally-maintained validation system that:

1. Lives within this repository for full control over updates
2. Stays synchronized with ECIP-1000 specifications
3. Supports all valid statuses defined in ECIP-1000 including WIP
4. Can be extended as new requirements emerge

Rationale

• Self-sufficiency: The ECIPs repository should not depend on external unmaintained tooling for core validation
• Consistency: Validation rules should match the actual ECIP-1000 specification
• Maintainability: Local tooling can be updated alongside specification changes
• Reliability: Eliminates CI failures caused by validator/spec drift

References

• ECIP-1000 - ECIP Process specification (defines WIP as valid status)
• Create ECIP-1120: Basefee Market with Miner Rewards #547
• Fix Olympia ECIPs categorization #550