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>

.github/workflows/live-tests.yml

@@ -0,0 +1,52 @@
+# ===----------------------------------------------------------------------===
+#
+# 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
+#
+# ===----------------------------------------------------------------------===
+
+name: Live tests
+
+on:
+  schedule:
+    # Every Monday at 06:00 UTC.
+    - cron: '0 6 * * 1'
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+jobs:
+  test:
+    name: Test against the live service
+    runs-on: macos-latest
+    steps:
+      - name: Check out
+        uses: actions/checkout@v4
+
+      - name: Select Xcode
+        uses: maxim-lobanov/setup-xcode@v1
+        with:
+          xcode-version: latest-stable
+
+      - name: Show toolchain
+        run: swift --version
+
+      - name: Cache build
+        uses: actions/cache@v4
+        with:
+          path: .build
+          key: spm-${{ runner.os }}-${{ hashFiles('Package.resolved') }}
+          restore-keys: spm-${{ runner.os }}-
+
+      - name: Test
+        run: make lib-test
+        env:
+          AMIIBO_LIVE_TESTS: '1'