Add PC/SC backend support for USB SIM readers

- Implemented a new `unsupportedBackend` in `backend_stub.go` to handle unsupported platforms.
- Created a `Service` struct in `service.go` to manage interactions with smart cards, including session management and identity reading.
- Added methods for reading identity, checking readiness, and authenticating with USIM applications.
- Introduced a `scriptedCard` for testing purposes in `service_test.go` to simulate card responses.
- Defined necessary types and error handling in `types.go` for better clarity and usability.
- Developed a `PCSCAdapter` in `vowifi/pcsc_adapter.go` to integrate PC/SC service with Wi-Fi calling functionalities.
- Added a new SVG icon for USB SIM readers in `public/sim-reader.svg`.
- Implemented tests to ensure correct functionality and error handling in various scenarios.

go.mod

@@ -3,6 +3,7 @@ module vocat
 go 1.25.0
 
 require (
+	github.com/ElMostafaIdrassi/goscard v1.0.0
 	github.com/coder/websocket v1.8.15
 	go.bug.st/serial v1.6.4
 	golang.org/x/crypto v0.41.0
@@ -14,6 +15,7 @@ require (
 require (
 	github.com/creack/goselect v0.1.2 // indirect
 	github.com/dustin/go-humanize v1.0.1 // indirect
+	github.com/ebitengine/purego v0.8.2 // indirect
 	github.com/google/uuid v1.6.0 // indirect
 	github.com/mattn/go-isatty v0.0.20 // indirect
 	github.com/ncruces/go-strftime v0.1.9 // indirect