feat: add Swift Package Manager support for iOS and macOS

[AmisKwok]

Summary / 摘要

Adds Swift Package Manager support for iOS and macOS and releases the package as 1.0.2. + 为 iOS 与 macOS 增加 Swift Package Manager 支持，并发布 1.0.2。

Changes / 变更

• Added Package.swift for iOS and macOS so the plugin resolves in SwiftPM-based projects; native sources moved to ios|macos/zero_network_kit/Sources/zero_network_kit/ and both podspecs were repointed at the new source_files / resource_bundles. / 新增 iOS 与 macOS 的 Package.swift，使插件可在 SwiftPM 工程中解析；原生源码移至 ios|macos/zero_network_kit/Sources/zero_network_kit/，两个 podspec 的 source_files 与 resource_bundles 同步指向新路径。
• Fixed the pub.dev description — it still advertised five platforms after Web support shipped; it now lists all six. / 修复 pub.dev 描述——Web 支持上线后仍只宣传五个平台，现列出全部六个。
• Fixed the macOS podspec template leftovers (placeholder summary, example.com homepage, Your Company author) and the iOS author, and enabled the privacy manifest resource bundle on both platforms. / 修复 macOS podspec 残留的模板值（占位 summary、example.com 主页、Your Company 作者）与 iOS 作者信息，并在两个平台启用隐私清单资源包。
• Bumped the version to 1.0.2 across pubspec.yaml, both podspecs, README.md, README_zh.md, CHANGELOG.md and the example lockfile; docs/ was rebuilt by the pre-commit sync hook. / 在 pubspec.yaml、两个 podspec、README.md、README_zh.md、CHANGELOG.md 与 example lockfile 中统一升级到 1.0.2；docs/ 由 pre-commit 同步钩子重建。
• Documented the dual distribution layout (CocoaPods podspec + Swift Package) in AGENTS.md and corrected the stale native source paths. / 在 AGENTS.md 中记录「CocoaPods + SwiftPM 双发布」布局，并修正已失效的原生源码路径。

Context / 背景

Projects that have migrated away from CocoaPods could not resolve the plugin at all, since only a podspec shipped. Adding a Swift Package manifest next to the existing podspec keeps both integration paths working without touching the public Dart API, so this is a patch release rather than a minor one. The doc/metadata fixes are bundled because both podspecs had to be edited anyway. / 已从 CocoaPods 迁移走的工程此前完全无法解析本插件（只提供了 podspec）。在保留 podspec 的同时新增 Swift Package 清单，两条集成路径都能工作，且未改动公开 Dart API，因此按补丁版本发布而非次版本。文档与元信息修复随本次一并提交，因为两个 podspec 本就需要改动。

Checklist / 检查项

• Title follows Conventional Commits / 标题符合约定式提交
• CI checks pass after merge / 合入后 CI 通过

Test plan

• flutter pub get, flutter analyze (no issues), dart format --set-exit-if-changed . (0 changed), flutter test (49/49 passed). / 本地四项校验全绿。
• Resolve the plugin in a SwiftPM-only iOS/macOS app and confirm getPlatformVersion / getNetworkDetails respond over the method channel. / 在纯 SwiftPM 的 iOS/macOS 工程中解析插件，确认方法通道可正常返回。
• Confirm the three required checks are green: Analyze & Test, Pana Score Check, Check PR Title (Conventional Commits). / 确认三项必需检查全部通过。

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