fix(testnet): port gov config from v0.38.x

[troian]

Description

Closes: #XXXX

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Author Checklist

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I have...

• included the correct type prefix in the PR title
• added ! to the type prefix if API or client breaking change
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• provided a link to the relevant issue or specification
• included the necessary unit and integration tests
• added a changelog entry to CHANGELOG.md
• included comments for documenting Go code
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[coderabbitai]

Caution

Review failed

The pull request is closed.

Walkthrough

The changes restructure the testnet governance configuration by introducing a new TestnetGovConfig type with a nested VotingParams structure to hold voting period parameters. Configuration initialization and related files are updated to reference the new nested structure.

Changes

Cohort / File(s)	Summary
Governance configuration restructuring app/testnet.go	Introduced TestnetGovConfig type with nested VotingParams struct containing VotingPeriod and ExpeditedVotePeriod fields. Updated TestnetConfig.Gov field type accordingly and adjusted initialization logic to read from the new nested structure.
Configuration type alignment cmd/akash/cmd/testnetify/config.go	Updated TestnetConfig.Gov field type from TestnetGov to TestnetGovConfig to reflect the restructured governance configuration.
Test fixture updates tests/upgrade/testnet.json	Added expedited_vote_period field alongside voting_period under the voting_params object.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~12 minutes

• Verify initialization logic correctly accesses nested VotingParams fields in app/testnet.go
• Confirm type changes in cmd/akash/cmd/testnetify/config.go are consistent with the new TestnetGovConfig structure
• Validate test fixture values align with expected configuration schema

Poem

🐰 A nest of params, now nested so tight,
Voting periods grouped, the structure's just right!
Governance governs with hierarchy new,
From flat into trees—what a structural view! 🌳

✨ Finishing touches

• 📝 Generate docstrings

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch testnetify1

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📜 Recent review details

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between fe4afca and 8f47869.

📒 Files selected for processing (3)

• app/testnet.go (3 hunks)
• cmd/akash/cmd/testnetify/config.go (1 hunks)
• tests/upgrade/testnet.json (1 hunks)

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