Add support of migrating with slot range

[bseto]

This PR addresses #214 somewhat.

From my understanding the current flow in the controller is:

# Step 1
clusterx migrate <slot range> <ID>  # to trigger a migration
# Step 2 - eventually after migration is over
clusterx setslot <slot range> <ID>  # to set the topology

These changes do not allow for:

1. The input parameter to accept multiple ranges
2. The range to stretch across multiple source shards.

This way, the controller does not need to be modified to perform multiple step 1s followed by step 2s

The main change is that MigrateSlotRequest accepts a SlotRange instead of a int.
slot = -1 used to mean no migration is happening. Now slot = nil is the equivalent.

// from
type MigrateSlotRequest struct {
	Target   int  `json:"target" validate:"required"`
	Slot     int  `json:"slot" validate:"required"`
	SlotOnly bool `json:"slot_only"`
}
// to
type MigrateSlotRequest struct {
	Target   int             `json:"target" validate:"required"`
	Slot     store.SlotRange `json:"slot" validate:"required"`
	SlotOnly bool            `json:"slot_only"`
}

[codecov-commenter]

Codecov Report

❌ Patch coverage is 57.94393% with 45 lines in your changes missing coverage. Please review.
✅ Project coverage is 46.11%. Comparing base (6c56470) to head (ef36d24).
⚠️ Report is 79 commits behind head on unstable.

Files with missing lines	Patch %	Lines
store/slot.go	77.46%	14 Missing and 2 partials ⚠️
controller/cluster.go	0.00%	14 Missing ⚠️
cmd/client/command/migrate.go	0.00%	5 Missing ⚠️
store/cluster.go	37.50%	4 Missing and 1 partial ⚠️
cmd/client/command/helper.go	0.00%	2 Missing ⚠️
store/cluster_node.go	33.33%	2 Missing ⚠️
store/cluster_shard.go	75.00%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##           unstable     #304      +/-   ##
============================================
+ Coverage     43.38%   46.11%   +2.73%     
============================================
  Files            37       45       +8     
  Lines          2971     4341    +1370     
============================================
+ Hits           1289     2002     +713     
- Misses         1544     2131     +587     
- Partials        138      208      +70     

Flag	Coverage Δ
unittests	46.11% <57.94%> (+2.73%)	⬆️

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[git-hulk]

@bseto Thanks for your contribution.

[Copilot]

Pull Request Overview

This PR refactors the migration functionality so that slot migration now works via slot ranges instead of individual slot IDs. The key changes include updating the MigrateSlotRequest type and its usage, refactoring various slot range functions (e.g., ParseSlotRange, AddSlotToSlotRanges, RemoveSlotFromSlotRanges), and adjusting associated tests and logging throughout the controller and client layers.

Reviewed Changes

Copilot reviewed 15 out of 15 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
store/slot_test.go	Updated tests for ParseSlotRange and slot range addition/removal logic
store/slot.go	Refactored slot range operations, including parsing and merging
store/cluster_shard.go	Updated Shard type to use pointer SlotRange for migrating slot
store/cluster_node.go	Changed MigrateSlot signature to use SlotRange
store/cluster.go	Updated shard lookup and migration logic to work with SlotRange
server/api/.go & controller/.go	Adjusted API endpoints, logging, and tests to operate on slot ranges
cmd/client/command/*.go	Modified CLI migration command to use string slot range input
consts/errors.go	Added error definitions relevant to new slot range migration

[git-hulk]

@bseto Thank you! Looks good to me. I will give a shot on my side.

[git-hulk]

@bseto Thank you!

[bseto]

@bseto Thank you!

No problem!