add new storage test panel

[cody-littley]

Describe your changes and provide context

In order to speed up test runtime, split storage unit tests into a stand alone panel.

I downloaded the logs from the new panels and from the old panels, and used an LLM to verify that the expected tests are running in each panel.

[github-actions]

The latest Buf updates on your PR. Results from workflow Buf / buf (pull_request).

Build	Format	Lint	Breaking	Updated (UTC)
✅ passed	✅ passed	✅ passed	✅ passed	May 21, 2026, 4:55 PM

[github-actions]

The latest Buf updates on your PR. Results from workflow Buf / buf (pull_request).

Build	Format	Lint	Breaking	Updated (UTC)
✅ passed	✅ passed	✅ passed	✅ passed	May 21, 2026, 4:49 PM

[cursor]

PR Summary

Medium Risk
Moderate CI risk: changes restructure test/coverage execution and package selection, which could inadvertently skip or double-run tests/coverage if package filtering or Codecov flags are misconfigured.

Overview
Splits the sei-db/state_db test suite into a new dedicated workflow state_db-tests.yml, running race tests and separate Codecov uploads/flags for that subtree.

Updates go-test.yml to exclude github.com/sei-protocol/sei-chain/sei-db/state_db from all test and coverage package lists (including PR fast-path reverse-dep selection), and adjusts the full-coverage job to build a single -coverpkg list from filtered packages to avoid clobbering coverage.out.

^{Reviewed by Cursor Bugbot for commit 712c704. Bugbot is set up for automated code reviews on this repo. Configure here.}

[masih]

I understand this the pre-step in more tests to come since today it won't make the slowest mandatory CI job any faster. Which means total wait time is unchanged.

No blockers regardless and glad to see experimentation here 🙌