Few fixes and improvements to the library, plus Github Actions setup (#31)

This PR contains the work done to fix a cancellation-mapping bug in `AmiiboLiveClient`, bring the client under offline test coverage, add the conformances SwiftUI and persistence need, and moves CI and documentation publishing to GitHub Actions. All public API changes are additive.

### Fix

- `AmiiboLiveClient` reported an early task cancellation as `.unknown("CancellationError()")`. The OpenAPI runtime wraps every error in `ClientError`, so the `CancellationError` check never matched; it now also checks the wrapped error and throws `.cancelled`.

### Tests

- `ThrowingTransport` and `StubTransport` test doubles let the live client run offline. New tests cover error mapping, HTTP status → error mapping, `oneOf` object-vs-list decoding, `"amiibo": null`, sorting, filter → query encoding, `Platform`/`Release` mapping, and the date transcoder.
- Models gained `package` memberwise initializers so tests can build real fixtures without `@testable`. These are not public API.
- The test target now depends on `OpenAPIRuntime` and `HTTPTypes` (both already in the dependency graph).

### API
- Models are `Codable` and `Identifiable` (`Amiibo.id` is its `identifier`; the key/name models use `key`).
- Filters are `Hashable`.

### Documentation
- Doc comments trimmed library-wide; one repeated `- Throws:` sentence appeared 24 times. `Library.md` and the README tightened to match.

### CI and docs publishing
- `ci.yml`: build and offline tests on PRs and pushes to `main`.
- `live-tests.yml`: weekly and on-demand run against the live API.
- `docs.yml`: builds DocC on PRs, deploys to GitHub Pages on `main`. Pinned to Xcode 26 because swift-docc-plugin 1.5.0 fails to launch its tools under Xcode 27.
- The generated `docs/` folder (327 files) is removed from the repository and ignored.

Reviewed-on: #31
Co-authored-by: Javier Cicchelli <javier@rock-n-code.com>

Tests/AmiiboService/Helpers/Fixtures/Fixtures.swift

@@ -0,0 +1,85 @@
+// ===----------------------------------------------------------------------===
+//
+// This source file is part of the Amiibo Service open source project
+//
+// Copyright (c) 2026 Röck+Cöde VoF. and the Amiibo Service project authors
+// Licensed under Apache license v2.0
+//
+// See LICENSE for license information
+// See CONTRIBUTORS for the list of Amiibo Service project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+// ===----------------------------------------------------------------------===
+
+import AmiiboService
+import Foundation
+
+/// Ready-made models for testing purposes.
+enum Fixtures {
+    /// Amiibo items; the first one has release dates and related games with usages.
+    static let amiibos: [Amiibo] = [
+        .init(
+            head: "01000000",
+            tail: "00040002",
+            name: "Zelda",
+            type: "Figure",
+            series: "Super Smash Bros.",
+            gameCharacter: "Zelda",
+            gameSeries: "The Legend of Zelda",
+            image: "https://raw.githubusercontent.com/N3evin/AmiiboAPI/master/images/icon_01000000-00040002.png",
+            release: .init(
+                america: Date(timeIntervalSince1970: 1_416_441_600),
+                australia: Date(timeIntervalSince1970: 1_417_564_800),
+                europe: Date(timeIntervalSince1970: 1_417_132_800),
+                japan: Date(timeIntervalSince1970: 1_417_564_800)
+            ),
+            platform: .init(
+                switch: [
+                    .init(
+                        identifiers: ["01007EF00011E000"],
+                        name: "The Legend of Zelda: Breath of the Wild",
+                        usages: [.init(explanation: "Spawns a random selection of items.", isWriteable: false)]
+                    )
+                ],
+                wiiU: [
+                    .init(
+                        identifiers: ["0005000010145000"],
+                        name: "Super Smash Bros. for Wii U",
+                        usages: [.init(explanation: "Unlocks a figure player.", isWriteable: true)]
+                    )
+                ]
+            )
+        ),
+        .init(
+            head: "00000000",
+            tail: "00000002",
+            name: "Mario",
+            type: "Figure",
+            series: "Super Smash Bros.",
+            gameCharacter: "Mario",
+            gameSeries: "Super Mario",
+            image: "https://raw.githubusercontent.com/N3evin/AmiiboAPI/master/images/icon_00000000-00000002.png"
+        )
+    ]
+    /// Amiibo series.
+    static let amiiboSeries: [AmiiboSeries] = [
+        .init(key: "0x00", name: "Super Smash Bros."),
+        .init(key: "0x01", name: "Super Mario")
+    ]
+    /// Amiibo types.
+    static let amiiboTypes: [AmiiboType] = [
+        .init(key: "0x00", name: "Figure"),
+        .init(key: "0x01", name: "Card")
+    ]
+    /// Game characters.
+    static let gameCharacters: [GameCharacter] = [
+        .init(key: "0x0000", name: "Mario"),
+        .init(key: "0x0100", name: "Zelda")
+    ]
+    /// Game series.
+    static let gameSeries: [GameSeries] = [
+        .init(key: "0x000", name: "Super Mario"),
+        .init(key: "0x010", name: "The Legend of Zelda")
+    ]
+}