[ISSUE #10641] Deprecate legacy Broker DLedger mode

[RongtongJin]

Summary

• deprecate the legacy Broker DLedger commit log and its MessageStoreConfig accessors
• log a startup warning when enableDLegerCommitLog=true
• preserve existing Broker DLedger behavior and leave the DLedger-backed Controller implementation unchanged

Motivation

Controller mode is the recommended automatic failover path for new deployments. Existing Broker DLedger deployments remain compatible; this change only adds API annotations and an opt-in startup warning.

Closes #10641

Test Plan

• mvn -pl broker,store -am -DskipITs -Dtest=BrokerStartupTest,DLedgerDeprecationTest -Dsurefire.failIfNoSpecifiedTests=false test
• 5 focused tests passed across 10 reactor modules
• Checkstyle reported 0 violations
• SpotBugs reported 0 findings

[codecov-commenter]

Codecov Report

❌ Patch coverage is 60.00000% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 48.24%. Comparing base (4f9b187) to head (bd95485).

Files with missing lines	Patch %	Lines
...java/org/apache/rocketmq/broker/BrokerStartup.java	75.00%	1 Missing ⚠️
...pache/rocketmq/store/dledger/DLedgerCommitLog.java	0.00%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@              Coverage Diff              @@
##             develop   #10642      +/-   ##
=============================================
- Coverage      48.34%   48.24%   -0.10%     
+ Complexity     13490    13470      -20     
=============================================
  Files           1380     1380              
  Lines         101025   101029       +4     
  Branches       13091    13091              
=============================================
- Hits           48837    48745      -92     
- Misses         46231    46306      +75     
- Partials        5957     5978      +21     

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