Some fixes to the live test suite (#32)

This PR contains the work done to fix the live test suite, which started failing once the Amiibo API began returning Switch 2 games, and tidies the test suite around it.

### Changes

- **Live tests:** replaced the assertion that the first amiibo has no Switch 2 games with a usage check, matching the other platforms. The live data now includes Switch 2 entries for most amiibos.
- **Live tests:** refreshed the minimum item counts and the earliest accepted last-updated date to the values observed in October 2026, and documented in the README how to refresh them.
- **All tests:** moved test descriptions from `@Test("...")` strings into backticked function names, and aligned every case on the same GIVEN/WHEN/THEN structure.
- **Live client:** replaced the TODO about DocC inherited docs with a note. The compiler does not inherit documentation for protocol witnesses, so the repeated doc comments stay on purpose.

Reviewed-on: #32
Co-authored-by: Javier Cicchelli <javier@rock-n-code.com>

Tests/AmiiboService/Cases/Public/Models/ModelConformanceTests.swift

@@ -21,8 +21,8 @@ struct ModelConformanceTests {
 
     // MARK: Identifiable tests
 
-    @Test("identifies an amiibo by its identifier")
-    func amiiboID() {
+    @Test
+    func `identifies an amiibo by its identifier`() {
         // GIVEN
         let amiibos = Fixtures.amiibos
 
@@ -31,8 +31,8 @@ struct ModelConformanceTests {
         #expect(amiibos.map(\.id) == amiibos.map(\.identifier))
     }
 
-    @Test("identifies key-name models by their keys")
-    func keyNameIDs() {
+    @Test
+    func `identifies key-name models by their keys`() {
         // GIVEN
         // WHEN
         // THEN
@@ -44,8 +44,8 @@ struct ModelConformanceTests {
 
     // MARK: Codable tests
 
-    @Test("round-trips amiibos through JSON")
-    func amiibosRoundTrip() throws {
+    @Test
+    func `round-trips amiibos through JSON`() throws {
         // GIVEN
         let amiibos = Fixtures.amiibos
 
@@ -57,8 +57,8 @@ struct ModelConformanceTests {
         #expect(decoded.first?.platform?.switch.first?.usages?.isEmpty == false)
     }
 
-    @Test("round-trips key-name models through JSON")
-    func keyNameRoundTrip() throws {
+    @Test
+    func `round-trips key-name models through JSON`() throws {
         // GIVEN
         // WHEN
         // THEN