fix disabled config verification

[AdoAdoAdo]

Reasoning behind the pull request

Proposed changes

Testing procedure

Pre-requisites

Based on the Contributing Guidelines the PR author and the reviewers must check the following requirements are met:

• was the PR targeted to the correct branch?
• if this is a larger feature that probably needs more than one PR, is there a feat branch created?
• if this is a feat branch merging, do all satellite projects have a proper tag inside go.mod?

[Copilot]

Pull request overview

This pull request tightens configuration validation around chain-parameters-by-epoch, addressing cases where validation could be bypassed or behave incorrectly (notably for disabled Supernova configurations and for in-place slice mutation during sorting).

Changes:

• Avoid mutating the caller-provided ChainParametersByEpoch slice by sorting a defensive copy inside NewChainParametersHolder.
• Reject duplicate EnableEpoch entries in chain parameters with a dedicated error (ErrDuplicateChainParametersEpoch) and add coverage for this.
• Make Supernova round-duration coherence checks order-independent by validating RoundDuration changes relative to epoch 0 prior to activation.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
sharding/errors.go	Adds a dedicated error for duplicate chain-parameters epochs.
sharding/chainParametersHolder.go	Sorts a copied slice (no caller mutation) and validates unique epochs in chain-parameters config.
sharding/chainParametersHolder_test.go	Adds tests for duplicate epochs, non-mutation of input slice, and updates ordering expectations.
factory/core/coreComponents.go	Refactors/centralizes round-duration validation to be order-independent and applied consistently.
factory/core/coreComponents_test.go	Updates and expands tests to cover disabled-supernova round-duration scenarios irrespective of ordering.

---

💡 Add a code-review agent skill or configure MCP servers for context-aware, tailored reviews. Learn more in the docs.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 77.72%. Comparing base (6b3e91d) to head (101d48c).

Additional details and impacted files

@@                 Coverage Diff                 @@
##           feat/testnet-fixes    #7963   +/-   ##
===================================================
  Coverage               77.71%   77.72%           
===================================================
  Files                     892      892           
  Lines                  129059   129078   +19     
===================================================
+ Hits                   100304   100330   +26     
+ Misses                  22203    22195    -8     
- Partials                 6552     6553    +1     

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.