Enhance GetStatsCmd to include additional options for backlog statistics

[freeznet]

fix #1800

• Added flags for precise backlog size, subscription backlog size, and earliest time in backlog.
• Updated doGetStats function to accept new parameters and utilize them in the stats retrieval process.
• Modified calls to GetPartitionedStats and GetStats to use the new options structure.

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[github-actions]

@freeznet:Thanks for your contribution. For this PR, do we need to update docs?
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[Copilot]

Pull Request Overview

Enhance the stats command to support new backlog-related options and ensure both partitioned and non-partitioned topics can leverage them.

• Added three new flags (--get-precise-backlog, --get-subscription-backlog-size, --get-earliest-time-in-backlog) and wired them through doGetStats
• Updated calls to use GetStatsWithOption and GetPartitionedStatsWithOption with a new GetStatsOptions struct
• Expanded test coverage by adding tests for each new flag and various flag combinations

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
pkg/ctl/topic/stats.go	Declared new boolean flags and passed them into doGetStats, then updated the underlying admin calls to use option-based helpers
pkg/ctl/topic/stats_test.go	Added unit tests to exercise precise backlog, subscription backlog, earliest-time flags, partitioned and per-partition stats

Comments suppressed due to low confidence (2)

pkg/ctl/topic/stats.go:146

• [nitpick] For consistency with the other flag-prefixed variables (getPreciseBacklog and getEarliestTimeInBacklog), consider renaming subscriptionBacklogSize to getSubscriptionBacklogSize.

var subscriptionBacklogSize bool

pkg/ctl/topic/stats_test.go:300

• [nitpick] This local variable defaultStats shadows the package-level defaultStats. Consider renaming it to expectedStats to avoid confusion.

defaultStats := utils.PartitionedTopicStats{