Fix truncation of Windows CPU hardware strings in systeminfo messages

### Task

Investigate and fix the issue where Windows CPU hardware strings are being truncated to a single character in systeminfo messages, ensuring the full CPU name is correctly read and recorded in replays.

### Context

In recent replays (specifically noticed in version 2026.06.04), the CPU hardware string reported by Windows users in the BAR systeminfo message is being truncated after the first character. For example, an Intel CPU is being recorded simply as "I" or "1".

This truncation is likely caused by the string being returned from the Windows registry in a wide-character (UTF-16) format (e.g., `I \0 n \0 t \0 e \0 l`). When standard C-string reading functions process this, they interpret the first null byte as the end of the string, causing premature termination. Fixing this string handling is necessary to accurately capture hardware telemetry and system information for debugging and analytics.

### Acceptance Criteria

* Identify the code responsible for reading the Windows CPU hardware string from the registry for systeminfo messages.
* Update the string handling to properly parse wide-character/UTF-16 strings, preventing premature null termination.
* Verify that the full CPU hardware string is correctly populated in the systeminfo message and fully visible in replays.
* Ensure the fix is platform-specific or safely implemented so it does not negatively impact hardware string reading on non-Windows platforms.

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Author: Bruno D
Discord: https://discord.com/channels/549281623154229250/724924957074915358/1501533773865418783
Model: gemini-3.1-pro-preview

Search the systeminfo message code for the Windows registry read that supplies the CPU hardware string; no file or test path is named in the issue. Trace how the registry value is converted and recorded, then verify that the complete CPU name appears in systeminfo messages and replays without changing non-Windows behavior.

Written by the indexing model from the issue text.