Add runtime test for IPC profiler command validation with truncated payloads

[Copilot]

Description

Adds runtime tests validating that the diagnostic server properly rejects IPC profiler commands when payload fields claim more data than actually exists. This covers the client_data_len validation at line 73 of ds-profiler-protocol.c as discussed in #122257.

Test cases added

• AttachProfilerCommand_TruncatedClientData_ReturnsError - client_data_len claims 1000 bytes, provides 0
• StartupProfilerCommand_TruncatedString_ReturnsError - profiler_path string length claims 1000 chars, provides 2
• AttachProfilerCommand_TruncatedGuid_ReturnsError - GUID field provides 8 bytes instead of 16

All tests verify the server returns DS_IPC_E_BAD_ENCODING (0x80131384).

Example payload construction

// Construct malformed AttachProfiler payload
using (var stream = new MemoryStream())
using (var writer = new BinaryWriter(stream))
{
    writer.Write((uint)1000);                    // attach_timeout
    writer.Write(Guid.NewGuid().ToByteArray());  // profiler_guid
    writer.Write((uint)(path.Length + 1));       // profiler_path length
    writer.Write(Encoding.Unicode.GetBytes(path + '\0'));
    writer.Write((uint)1000);                    // client_data_len (claims 1000)
    // Intentionally omit actual client_data bytes
}

Original prompt

Can you add an runtime test that validates the behavior when the diagnostic server parses an IPC profiler command that has less data than the client_data_len suggests, as brought up in #122257 (comment). Ideally it would be through using the Microsoft.Diagnostics.NETCore.Client library, but I'm guessing that might not expose an api that allows customization of the client data bytes passed

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