Add asc-client v0.1.0

Swift CLI for the App Store Connect API. Commands for managing apps,
versions, localizations, screenshots/previews, builds, and review
submission. Includes interactive credential setup and media upload
with retry support for stuck processing items.

.gitignore

@@ -0,0 +1,10 @@
+.DS_Store
+/.build
+/Packages
+/.claude
+*.xcodeproj
+xcuserdata/
+DerivedData/
+.swiftpm/configuration/registries.json
+.swiftpm/xcode/package.xcworkspace/contents.xcworkspacedata
+.netrc