initialize cluster slots with the current root bank

[jstarry]

Problem

During the first 200ms of starting up cluster slots service, no root epoch is available to determine repair request weighting

[2025-08-04T07:55:24.542156419Z ERROR solana_core::cluster_slots_service::cluster_slots] No epoch info for slot 357756098
[2025-08-04T07:55:24.560481761Z ERROR solana_core::cluster_slots_service::cluster_slots] No epoch info for slot 357756137
..
[2025-08-04T07:55:24.642578024Z ERROR solana_core::cluster_slots_service::cluster_slots] No epoch info for slot 357770520
[2025-08-04T07:55:24.655027149Z ERROR solana_core::cluster_slots_service::cluster_slots] No epoch info for slot 357772008
[2025-08-04T07:55:24.690908053Z INFO  solana_core::cluster_slots_service::cluster_slots] Updating epoch_metadata for epoch 828

Summary of Changes

Initialize the root epoch when starting up the cluster slots service

Fixes #

[alexpyattaev]

LGTM thank you!

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 82.8%. Comparing base (37eb5cc) to head (7927a8b).

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #7314   +/-   ##
=======================================
  Coverage    82.8%    82.8%           
=======================================
  Files         801      801           
  Lines      363300   363304    +4     
=======================================
+ Hits       300834   300856   +22     
+ Misses      62466    62448   -18     

🚀 New features to boost your workflow:

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

[mergify]

Backports to the beta branch are to be avoided unless absolutely necessary for fixing bugs, security issues, and perf regressions. Changes intended for backport should be structured such that a minimum effective diff can be committed separately from any refactoring, plumbing, cleanup, etc that are not strictly necessary to achieve the goal. Any of the latter should go only into master and ride the normal stabilization schedule. Exceptions include CI/metrics changes, CLI improvements and documentation updates on a case by case basis.