Fix missing DenomUnits in v6 denom metadata migration

[metalarm10]

Description

The v6 upgrade updated Display to "tx" but missed updating DenomUnits - it still has "core" at exponent 6. This blocks the Cosmos Chain Registry update (cosmos/chain-registry#7564) since the CI requires Display to match a DenomUnits entry.

This adds a new upgrade handler v6_fix_denom_metadata that renames DenomUnits[exponent=6] from "core" to "tx" to match Display.

Will be Released as v6.1.0.

Reviewers checklist:

• Try to write more meaningful comments with clear actions to be taken.
• Nit-picking should be unblocking. Focus on core issues.

Authors checklist

• Provide a concise and meaningful description
• Review the code yourself first, before making the PR.
• Annotate your PR in places that require explanation.
• Think and try to split the PR to smaller PR if it is big.

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This change is 

[miladz68]

@miladz68 reviewed 4 files and all commit messages, and made 4 comments.
Reviewable status: all files reviewed, 4 unresolved discussions (waiting on masihyeganeh, metalarm10, and TxCorpi0x).

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app/upgrade/v6_fix_denom_metadata/upgrade.go line 1 at r1 (raw file):

package v6fixdenommetadata

I have 3 comments on this file, based on the previous way of how we handled these types of upgrades, containing patches of changes. feel free to ignore if there is specific reason to do so.

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app/upgrade/v6_fix_denom_metadata/upgrade.go line 3 at r1 (raw file):

package v6fixdenommetadata

import (

the folder structure should be upgrade/v6/upgrade.go and the pacakge should still be called v6.

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app/upgrade/v6_fix_denom_metadata/upgrade.go line 15 at r1 (raw file):

// Name defines the upgrade name.
const Name = "v6_fix_denom_metadata"

we should call the upgrade something more general, like v6patch1 orv6_1.

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app/upgrade/v6_fix_denom_metadata/upgrade.go line 18 at r1 (raw file):

// New makes an upgrade handler for v6_fix_denom_metadata upgrade.
func New(

we should call this NewV6Pach1

[ysv]

@ysv reviewed 4 files and all commit messages, and made 1 comment.
Reviewable status: all files reviewed, 4 unresolved discussions (waiting on masihyeganeh, metalarm10, miladz68, and TxCorpi0x).

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app/upgrade/v6_fix_denom_metadata/upgrade.go line 1 at r1 (raw file):

Previously, miladz68 (milad) wrote…

I have 3 comments on this file, based on the previous way of how we handled these types of upgrades, containing patches of changes. feel free to ignore if there is specific reason to do so.

Yeah these are reasonable comments.
But because of time-constrain it is ok to keep it as it is.

[TxCorpi0x]

@TxCorpi0x reviewed 4 files and all commit messages.
Reviewable status: all files reviewed, 4 unresolved discussions (waiting on masihyeganeh, metalarm10, and miladz68).

[TxCorpi0x]

Since we are goting to resolve this issue, we need to make sure this CI script passes
https://github.com/cosmos/chain-registry/actions/runs/22759148426/job/66011597563?pr=7564
The script that needs to pass, it would be good to run the script locally and make sure it passes with a local znet (if possible simply)
https://github.com/cosmos/chain-registry/blob/master/.github/workflows/utility/validate_data.mjs

@TxCorpi0x made 1 comment.
Reviewable status: all files reviewed, 4 unresolved discussions (waiting on masihyeganeh, metalarm10, and miladz68).

[miladz68]

@miladz68 resolved 4 discussions.
Reviewable status: complete! all files reviewed, all discussions resolved.