refactor(csharp): update integer properties to unsigned types for consistency

[lukaszzborek]

No description provided.

[codecov]

Codecov Report

❌ Patch coverage is 91.71779% with 27 lines in your changes missing coverage. Please review.
✅ Project coverage is 85.10%. Comparing base (d3028f9) to head (0d1003f).

Files with missing lines	Patch %	Lines
foreign/csharp/Iggy_SDK/Mappers/BinaryMapper.cs	89.85%	16 Missing and 5 partials ⚠️
...n/csharp/Iggy_SDK/Consumers/IggyConsumer.Rented.cs	75.00%	1 Missing and 1 partial ⚠️
foreign/csharp/Iggy_SDK/Consumers/IggyConsumer.cs	84.61%	2 Missing ⚠️
...eign/csharp/Iggy_SDK/Contracts/Tcp/TcpContracts.cs	96.72%	0 Missing and 2 partials ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #4027      +/-   ##
============================================
+ Coverage     85.05%   85.10%   +0.04%     
  Complexity     1402     1402              
============================================
  Files          1237     1236       -1     
  Lines        181722   181699      -23     
  Branches     148015   148003      -12     
============================================
+ Hits         154567   154629      +62     
+ Misses        23098    23047      -51     
+ Partials       4057     4023      -34     

Components	Coverage Δ
Rust Core	86.11% <ø> (ø)
Java SDK	67.29% <ø> (ø)
C# SDK	76.33% <91.71%> (+0.93%)	⬆️
Python SDK	90.06% <ø> (ø)
PHP SDK	85.65% <ø> (ø)
Node SDK	94.50% <ø> (ø)
Go SDK	69.28% <ø> (ø)

Files with missing lines	Coverage Δ
...ign/csharp/Iggy_SDK/Contracts/Auth/AuthResponse.cs	100.00% <100.00%> (ø)
foreign/csharp/Iggy_SDK/Contracts/ClientInfo.cs	100.00% <ø> (ø)
...reign/csharp/Iggy_SDK/Contracts/MessageResponse.cs	100.00% <100.00%> (ø)
...oreign/csharp/Iggy_SDK/Contracts/PolledMessages.cs	14.28% <100.00%> (+14.28%)	⬆️
.../csharp/Iggy_SDK/Contracts/PolledMessagesRental.cs	100.00% <ø> (ø)
...csharp/Iggy_SDK/Contracts/RentedMessageResponse.cs	100.00% <100.00%> (ø)
foreign/csharp/Iggy_SDK/Contracts/StatsResponse.cs	100.00% <ø> (ø)
...oreign/csharp/Iggy_SDK/Contracts/StreamResponse.cs	100.00% <ø> (ø)
foreign/csharp/Iggy_SDK/Identifier.cs	75.92% <100.00%> (-2.41%)	⬇️
...oreign/csharp/Iggy_SDK/IggyClient/IIggyConsumer.cs	50.00% <ø> (ø)
... and 9 more

... and 2 files with indirect coverage changes

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[hubcio]

outside the diff:

• TcpContracts.cs:282 - stream.Topics != null has the same empty-dictionary bug you fixed for Streams: an empty Topics writes has_topics = 1 with no entries and the server rejects the request. same is { Count: > 0 } here and at line 347.
• TcpContracts.cs:151 - UpdatePermissions(userId, null) sizes the buffer without the has-permissions byte, then writes it at line 167. index out of range on the documented default permissions = null.
• BinaryFactory.cs:155 - CreatePartitionPayload has no callers and throws on first use (16-byte buffer, 8-byte writes at offsets 12 and 16). delete it.

[spetz]

Looks good, here are 2 extra things to improve outisde the scope of this PR, so feel free to either update this PR or we can add these to the next one.

foreign/csharp/Iggy_SDK/Vsr/ConsumerGroupClientState.cs:46 - an empty cached assignment is treated as missing, causing repeated synchronization and a possible hot loop when PollingIntervalMs is 0. Consider preserving empty assignments and returning the 0xFFFF_FFFE no-assignment sentinel with backoff.

foreign/csharp/Iggy_SDK/Mappers/BinaryMapper.cs:803 - the options-length prefix is read without confirming four bytes remain, so truncated input throws ArgumentOutOfRangeException instead of MalformedResponseException. Consider reusing ReadLength.

[lukaszzborek]

2 extra comments from @spetz was also done in this PR

[hubcio]

went through all 21 comments from the last round against the code - every one is genuinely fixed, and the unit suite is green locally (1028 tests across net8.0 and net10.0, 0 build warnings). the MapHeaders rewrite onto shared ReadHeaderKind / ReadHeaderField and the ArrayBufferWriter permissions pass came out cleaner than what I asked for.

two things live outside the diff so I could not anchor them:

Iggy_SDK_Tests/VsrTests/SyncConsumerGroupTests.cs - nothing covers the sentinel this fix is built on. neither the PollGroupMessagesRentedAsync return nor the consumer backoff has a test, while go covers both in tcp_group_polling_test.go:262 and :279. the assert that actually guards the HasAssignment change is that a second poll issues no new SYNC_CONSUMER_GROUP.

Iggy_SDK/IggyClient/IIggyConsumer.cs:45 and :57 - PollMessagesAsync and PollMessagesRentedAsync are public and do not say PartitionId can come back as NO_ASSIGNED_PARTITION with an empty batch. go states it in the interface contract (contracts/client.go:128). anyone using the raw poll instead of IggyConsumer would key offsets on partition 4294967294.