Upload API — Invoke-CurseForgeUploadAPI private client

[MariusStorhaug]

Parent: #11

Implement Invoke-CurseForgeUploadAPI — the private client function for the site-relative Upload API.

Acceptance criteria:

• Invoke-CurseForgeUploadAPI is a private function under src/functions/private/Upload/
• Resolves context token from vault via Resolve-CurseForgeContext
• Base URL pattern: https://{game}.curseforge.com/api/ — game slug resolved from context or parameter
• Auth header: X-Api-Token: {token} (different from Core API)
• Supports GET, POST, PATCH methods
• Handles multipart/form-data for file uploads
• Error handling returns meaningful messages from API error responses
• Unit tests cover URL construction and auth header placement

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• Create src/functions/private/Upload/Invoke-CurseForgeUploadAPI.ps1
• Create tests/Upload/Invoke-CurseForgeUploadAPI.Tests.ps1