Update PyManager build to use 3.14.0rc2 (#154)

Build with 3.14.0rc1

Separate default install tag from default launch tag. (#146)

This 'fixes' issues people have where they want the prerelease installer but not prerelease Python.
At 3.14's release, we'll remove the default config setting that installs 3-dev.
Fixes #122

Merges newly downloaded packages into existing index.json. (#132)

Fixes #131

Build using 3.14.0b2 (#120)

Improve list help and adds list -f=formats. (#113)

Fixes #55

Improves purging and shortcut removal. (#103)

Fixes #102

Adds fallback search for 'python<TAG>.exe' style shebangs. (#97)

Fixes #91

Ensure launcher suffix always has a dot. (#76)

Fixes #75

Update PyManager to use 3.14.0b1 runtime (#71)