add CI process for Windows code-signing

[lyc8503]

:rocket:	This description was created by Ellipsis for commit 74a3e4dce36f8b83a11beabd8ace2a5e1bc6add6

Summary:

Added Windows code-signing step to CI using dlemstra/code-sign-action@v1 in .github/workflows/build.yml.

Key points:

• Added Windows code-signing step in .github/workflows/build.yml
• Uses dlemstra/code-sign-action@v1 for code-signing
• Executes only on Windows runners (if: runner.os == 'Windows')
• Uses secrets CERTIFICATE and CERTIFICATE_PASSWORD
• Signs files in dist folder recursively
• Description set to Activity Watch

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Generated with :heart: by ellipsis.dev

[lyc8503]

This should close #181 #632