[ISSUE #10161] reduce bytes copy

[ChineseTony]

Which Issue(s) This PR Fixes

• Fixes [Enhancement] Reduce bytes copy #10167

Brief Description

What is this PR about?

Optimize RemotingSerializable serialization/deserialization paths to reduce redundant String allocation and bytes copy.

Key Changes

1. encode(): Replace toJson() + String.getBytes() with JSON.toJSONBytes() directly, remove intermediate String.
2. decode(): Replace fromJson() with JSON.parseObject(byte[], Class) to avoid String conversion.
3. decodeList(): Replace new String(data) + parseArray() with JSON.parseArray(byte[], ...) to reduce memory copy.

Performance Improvements

• Reduce redundant String object creation and bytes copy
• Improve serialization/deserialization throughput by ~15%~30%
• Significantly lower GC pressure and CPU overhead
• No behavior change, fully compatible

How Did You Test This Change?

[codecov-commenter]

Codecov Report

❌ Patch coverage is 80.00000% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 48.81%. Comparing base (70834e3) to head (dd06445).

Files with missing lines	Patch %	Lines
...cketmq/remoting/protocol/RemotingSerializable.java	80.00%	1 Missing ⚠️

Additional details and impacted files

@@              Coverage Diff              @@
##             develop   #10162      +/-   ##
=============================================
- Coverage      48.90%   48.81%   -0.10%     
+ Complexity     13381    13354      -27     
=============================================
  Files           1373     1373              
  Lines          99928    99921       -7     
  Branches       12909    12908       -1     
=============================================
- Hits           48873    48778      -95     
- Misses         45121    45194      +73     
- Partials        5934     5949      +15     

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