Redesign product homepage and add Homebrew install (#5)

Author: TREAFREE

README.md

@@ -66,14 +66,23 @@ See the [format matrix](docs/FORMAT_MATRIX.md) for the exact verified input and
 
 ## Download, install, and use
 
+Install with Homebrew:
+
+```sh
+brew install --cask treafree/tap/file-island
+```
+
+Or install the DMG manually:
+
 1. Download the DMG and matching SHA-256 from [GitHub Releases](https://github.com/TREAFREE/FileIsland/releases/latest).
 2. Verify the checksum, open the DMG, and drag **File Island.app** to **Applications**.
-3. Launch it from Applications, then drag media or a folder from Finder to the Island at the top of the screen.
-4. Configure the image, video, and audio groups and choose **Start**.
-5. Authorize a persistent output folder on first use, then reveal the results in Finder.
+
+Then launch File Island from Applications, drag media or a folder from Finder to the Island at the top of the screen, configure each media group, and choose **Start**. Authorize a persistent output folder on first use; later conversions reuse that folder automatically.
 
 The current early-access build is not signed with Apple Developer ID and is not notarized. macOS may block its first launch. Try to open it once, then use **System Settings → Privacy & Security → Open Anyway** only for a checksum-verified DMG from this repository's official Release. Never disable Gatekeeper.
 
+The Homebrew cask installs the same unsigned release artifact, so the same first-launch warning may apply. Future releases require a version and checksum update in the [`TREAFREE/homebrew-tap`](https://github.com/TREAFREE/homebrew-tap) repository before `brew upgrade --cask file-island` can install them.
+
 For illustrated, step-by-step videos, read the [complete user guide](docs/USER_GUIDE.md).
 
 ## Demos

README.zh-CN.md

@@ -66,14 +66,23 @@ File Island 不试图替代专业剪辑软件，也不会声称支持尚未验
 
 ## 下载、安装与使用
 
+使用 Homebrew 安装：
+
+```sh
+brew install --cask treafree/tap/file-island
+```
+
+或者手动安装 DMG：
+
 1. 从 [GitHub Releases](https://github.com/TREAFREE/FileIsland/releases/latest) 下载 DMG 和对应 SHA-256；
-2. 核对校验值，打开 DMG，将 **File Island.app** 拖入 **Applications（应用程序）**；
-3. 从“应用程序”启动，然后把访达中的媒体或文件夹拖到屏幕顶部；
-4. 分别选择图片、视频和音频参数，点击 **Start**；
-5. 首次转换时选择一个固定输出文件夹，完成后在访达中查看结果。
+2. 核对校验值，打开 DMG，将 **File Island.app** 拖入 **Applications（应用程序）**。
+
+然后从“应用程序”启动 File Island，把访达中的媒体或文件夹拖到屏幕顶部，分别设置不同媒体类型的参数并点击 **Start**。首次转换时选择一个固定输出文件夹，以后的转换会自动复用该文件夹。
 
 当前 early-access 版本尚未使用 Apple Developer ID，也没有经过 Apple 公证。macOS 第一次可能会阻止启动；请先尝试打开一次，再到 **系统设置 → 隐私与安全性 → 仍要打开**。只应对来自本仓库官方 Release 且校验值匹配的安装包这样操作，不要关闭 Gatekeeper。
 
+Homebrew Cask 安装的是同一个未签名 Release，因此第一次启动时也可能出现相同提示。以后每次发布新版，都需要先更新 [`TREAFREE/homebrew-tap`](https://github.com/TREAFREE/homebrew-tap) 中的版本号和校验值，用户随后才能通过 `brew upgrade --cask file-island` 升级。
+
 图文与分步骤视频见：[File Island 完整中文教程](docs/USER_GUIDE.zh-CN.md)。
 
 ## 演示

docs/USER_GUIDE.md

@@ -4,6 +4,14 @@
 
 File Island keeps conversion work on your Mac. The DMG includes the required FFmpeg, ffprobe, and media-validation runtime; Homebrew, Python, Node.js, and separate codec packages are not required.
 
+If you already use Homebrew, you can install the same release directly:
+
+```sh
+brew install --cask treafree/tap/file-island
+```
+
+The app is currently unsigned and not notarized, so continue with the first-launch instructions below even when it was installed by Homebrew.
+
 ## 1. Download and verify
 
 1. Open the official [GitHub Releases](https://github.com/TREAFREE/FileIsland/releases/latest) page.

docs/USER_GUIDE.zh-CN.md

@@ -4,6 +4,14 @@
 
 File Island 会把转换工作留在你的 Mac 上。安装包已经包含应用需要的 FFmpeg、ffprobe 和媒体校验工具，不需要另外安装 Homebrew、Python、Node.js 或任何编解码器包。
 
+如果你已经在使用 Homebrew，也可以直接安装同一个 Release：
+
+```sh
+brew install --cask treafree/tap/file-island
+```
+
+当前应用尚未签名和公证，所以即使通过 Homebrew 安装，第一次运行时仍需按照下方说明手动确认。
+
 ## 1. 下载并核对安装包
 
 1. 打开项目的 [GitHub Releases](https://github.com/TREAFREE/FileIsland/releases/latest) 页面。