refactor(java): unify blocking TCP client as wrapper over async client

[mmodzelewski]

The blocking TCP client had its own independent protocol
implementation via InternalTcpClient using Reactor Netty.
This duplicated all serialization, request/response handling,
and connection logic already present in the async client.

Replace InternalTcpClient with thin delegation to
AsyncIggyTcpClient, resolving CompletableFutures via
FutureUtil.resolve(). This eliminates ~900 lines of
duplicated protocol code and the Reactor dependency,
replacing it with direct Netty modules.

[codecov]

Codecov Report

❌ Patch coverage is 89.89899% with 10 lines in your changes missing coverage. Please review.
✅ Project coverage is 70.44%. Comparing base (25dcd76) to head (d40cfad).
⚠️ Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
...rg/apache/iggy/client/blocking/tcp/FutureUtil.java	40.00%	5 Missing and 1 partial ⚠️
...iggy/client/blocking/tcp/IggyTcpClientBuilder.java	85.71%	2 Missing ⚠️
...apache/iggy/client/blocking/tcp/IggyTcpClient.java	93.33%	1 Missing ⚠️
...ache/iggy/client/blocking/tcp/SystemTcpClient.java	85.71%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #2947      +/-   ##
============================================
+ Coverage     70.25%   70.44%   +0.19%     
+ Complexity      925      909      -16     
============================================
  Files          1033     1029       -4     
  Lines         85665    84844     -821     
  Branches      63040    62427     -613     
============================================
- Hits          60182    59772     -410     
+ Misses        22982    22582     -400     
+ Partials       2501     2490      -11     

Flag	Coverage Δ
java	61.57% <89.89%> (-0.79%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
...gy/client/async/tcp/AsyncIggyTcpClientBuilder.java	77.27% <100.00%> (ø)
...y/client/blocking/tcp/ConsumerGroupsTcpClient.java	100.00% <100.00%> (ø)
.../client/blocking/tcp/ConsumerOffsetsTcpClient.java	100.00% <100.00%> (ø)
...he/iggy/client/blocking/tcp/MessagesTcpClient.java	100.00% <100.00%> (+3.33%)	⬆️
.../iggy/client/blocking/tcp/PartitionsTcpClient.java	100.00% <100.00%> (ø)
...nt/blocking/tcp/PersonalAccessTokensTcpClient.java	100.00% <100.00%> (ø)
...che/iggy/client/blocking/tcp/StreamsTcpClient.java	100.00% <100.00%> (ø)
...ache/iggy/client/blocking/tcp/TopicsTcpClient.java	100.00% <100.00%> (ø)
...pache/iggy/client/blocking/tcp/UsersTcpClient.java	100.00% <100.00%> (+7.93%)	⬆️
...apache/iggy/client/blocking/tcp/IggyTcpClient.java	57.44% <93.33%> (-2.56%)	⬇️
... and 3 more

... and 44 files with indirect coverage changes

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.