• chore: loadShards changes to more cleanly support 2.x feature (chore: loadShards changes to more cleanly support 2.x feature #25513)

• chore: move shardID parsing and shard filtering into walkShardsAndProcess

• chore: make it impossible to miss sending shardResponse or marking shard as complete

• chore: always count number of shards (preparation for 2.x related feature)

• chore: explicitly load series files and create indices serially

Explicitly load series files and create indices serially. Also avoid passing them to work functions that don't need them.

• chore: rework loadShards for changes necessary to cancel loading process

• chore: comment improvements

• fix: fix race conditions in TestStore_StartupShardProgress and TestStore_BadShardLoading

• chore: avoid logging nil error

• chore: refactor shard loading and shard walking

Refactor loadShards and CreateShard to use a common shardLoader class that makes thread-safety easier. Refactor walkShardsAndProcess into findShards.

• chore: improve comment

• chore: rename OpenShard to ReopenShard and implement with shardLoader

Rename Store.OpenShard to Store.ReopenShard and implement using a shardLoader object. Changes to tests as necessary.

• chore: avoid resetting shard options and locking on Reopen

Avoid resetting shard options when reopening a shard. Proper mutex locker in Shard.ReopenShard.

• chore: fix formatting issue

• chore: warn on mixed index types in Store.CreateShard

• chore: change from info to warn when invalid shard IDs found in path

• chore: use coarser locking in Store.ReopenShard

• chore: fix typo in comment

• chore: code simplification

(cherry picked from commit 0bc167b)

• chore: fix logging issues in Store.loadShards

Fix reporting shards not opening correctly when they actually did. Fix race condition with logging in loadShards.

(cherry picked from commit 65683bf)

• chore: remove unnecessary fmt.Sprintf calls

Remove unnecessary fmt.Sprintf calls for static code checks in main-2.x.

(cherry picked from commit 8497fbf)

• chore: remove unnecessary blank identifier

• chore: remove unnecessary blank identifier

(cherry picked from commit 5c7479e)

Closes: #25555

Closes #

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