fix(ci): align winget release asset URLs with published artifacts

[694410194]

Summary

• point the winget workflow at the published cortex-cli-windows-*.zip release assets
• derive manifest repository links from the current GitHub repository instead of the stale cortex-cli path
• keep the arm64 branch optional when the asset is absent

Verification

• git diff --check
• ruby -e 'require "yaml"; YAML.load_file(".github/workflows/winget.yml"); puts "yaml-ok"'

Fixes #53208
/claim #53208

[greptile-apps]

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