[ISSUE #9735] Add TimerWheel snapshot mechanism for reliable recovery

[guyinyou]

• Add snapshot backup and recovery functionality to TimerWheel
• Add configuration options for snapshot control with backward compatibility
• Implement atomic flush operations with synchronization locks
• Add snapshot file management (creation, cleanup, selection)
• Support recovery from snapshot files to avoid rebuilding TimerWheel
• Add TimerFlushService.flush() method for manual flush operations

This addresses the issue where discrete TimerWheel state cannot be recovered from TimerLog alone, ensuring data consistency and improving recovery performance.

Configuration changes:

• timerWheelSnapshotFlush: enable/disable snapshot functionality (default: false)
• timerWheelDefaultFlush: enable/disable default flush behavior (default: true)
• timerWheelSnapshotIntervalMs: snapshot creation interval (default: 10s)

Change-Id: I801ce7ca6330d02aefcae905e59e1e2b7642ebf5

Which Issue(s) This PR Fixes

Fixes #9735

Brief Description

How Did You Test This Change?

[codecov-commenter]

Codecov Report

❌ Patch coverage is 26.36364% with 81 lines in your changes missing coverage. Please review.
✅ Project coverage is 48.10%. Comparing base (64999c1) to head (c4a54dd).

Files with missing lines	Patch %	Lines
...va/org/apache/rocketmq/store/timer/TimerWheel.java	15.62%	51 Missing and 3 partials ⚠️
...apache/rocketmq/store/timer/TimerMessageStore.java	42.10%	19 Missing and 3 partials ⚠️
...ache/rocketmq/store/config/MessageStoreConfig.java	37.50%	5 Missing ⚠️

Additional details and impacted files

@@              Coverage Diff              @@
##             develop    #9736      +/-   ##
=============================================
- Coverage      48.20%   48.10%   -0.11%     
+ Complexity     12168    12145      -23     
=============================================
  Files           1313     1313              
  Lines          93340    93424      +84     
  Branches       11962    11977      +15     
=============================================
- Hits           44997    44942      -55     
- Misses         42771    42900     +129     
- Partials        5572     5582      +10     

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