Add UTF-8 encoding to file operations in update-agent-context.ps1

[stenyin]

Ensure file read/write operations in update-agent-context.ps1 use UTF-8 encoding for better compatibility.

[Copilot]

Pull Request Overview

This PR adds UTF-8 encoding to file read/write operations in the update-agent-context.ps1 PowerShell script to ensure better compatibility when handling files that may contain special characters or international text.

• Adds -Encoding utf8 parameter to all Get-Content cmdlets
• Adds -Encoding utf8 parameter to all Set-Content cmdlets

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[Copilot]

Copilot wasn't able to review any files in this pull request.

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