docs(getting-started/en): sync installation and API key improvements

- Windows/macOS: add estimated install time tip
- Windows/macOS: add Troubleshooting section
- Linux: add experienced-user quick-start TL;DR
- configure-api-key: add skip hint for cloud users + key security note

Author: yi-ge

i18n/en/docusaurus-plugin-content-docs/current/01-getting-started/02-installation/01-windows.md

@@ -8,6 +8,10 @@ keywords: [Windows, installation, NSIS, SmartScreen]
 
 This guide covers how to install DesireCore on Windows.
 
+:::tip Estimated time
+The entire installation typically takes just **1–2 minutes** (depending on download speed).
+:::
+
 ## Installation Steps
 
 1. **Download the installer**
@@ -81,4 +85,10 @@ To uninstall DesireCore:
 During uninstallation, you'll be asked whether to also delete application data. If you plan to reinstall, it's recommended to keep the data; if you're sure you won't use it again, you can choose to delete everything.
 :::
 
+## Troubleshooting
+
+- **Installer won't open**: Verify the download completed successfully (file size ~100–200 MB), then try downloading again.
+- **Antivirus blocks installation**: Add the DesireCore install directory to your antivirus allowlist, or temporarily disable real-time protection and retry.
+- **Other issues**: Visit the [FAQ](../../06-faq/index.md) or contact our support team.
+
 After installation, head to [First Run](../03-first-run.md) to learn about the post-launch onboarding flow.

i18n/en/docusaurus-plugin-content-docs/current/01-getting-started/02-installation/02-macos.md

@@ -8,6 +8,10 @@ keywords: [macOS, installation, DMG, Gatekeeper, Apple Silicon, Intel]
 
 This guide covers how to install DesireCore on macOS.
 
+:::tip Estimated time
+The entire installation typically takes just **1 minute** — download the DMG, drag to Applications, done.
+:::
+
 ## Installation Steps
 
 1. **Download the DMG file**
@@ -76,4 +80,11 @@ To also remove application data, delete the following directories:
 ~/.desirecore/
 ```
 
+## Troubleshooting
+
+- **DMG won't open**: Verify the download completed successfully, then try downloading again.
+- **"is damaged and can't be opened" message**: This is usually Gatekeeper blocking the app — follow the "Handling Gatekeeper Prompts" section above.
+- **Slow performance on Apple Silicon**: Confirm you downloaded the arm64 version, not x64 (Rosetta translation incurs a performance penalty).
+- **Other issues**: Visit the [FAQ](../../06-faq/index.md) or contact our support team.
+
 After installation, head to [First Run](../03-first-run.md) to learn about the post-launch onboarding flow.

i18n/en/docusaurus-plugin-content-docs/current/01-getting-started/02-installation/03-linux.md

@@ -8,6 +8,15 @@ keywords: [Linux, installation, AppImage, Ubuntu, Fedora, ARM64, UnionTech UOS,
 
 This guide covers how to install DesireCore on Linux. DesireCore is distributed as an AppImage, supporting both x64 and ARM64 architectures, and is compatible with most mainstream Linux distributions, including Chinese domestic operating systems such as UnionTech UOS, Kylin OS, Deepin, and openKylin.
 
+:::tip Experienced users — quick start
+```bash
+# Two commands after downloading:
+chmod +x DesireCore_x86_64_*.AppImage
+./DesireCore_x86_64_*.AppImage
+```
+If you hit a sandbox error, jump to [Troubleshooting](#troubleshooting-sandbox-errors).
+:::
+
 :::tip Chinese Domestic OS Users
 DesireCore has been tested and verified on UnionTech UOS, Kylin OS, Deepin, openKylin, and other Chinese domestic operating systems. For platform-specific installation instructions and compatibility details, please visit the [DesireCore China website](https://www.desirecore.cn).
 :::

i18n/en/docusaurus-plugin-content-docs/current/01-getting-started/04-configure-api-key.md

@@ -15,6 +15,10 @@ DesireCore is a local-first application: core data is stored locally by default.
 | Official cloud compute | Users who do not want to register with each model provider first | Sign in to bind the `desirecore-cloud` provider and use a subscription or credits |
 | Your own API key | Existing provider accounts, direct cost control, or enterprise compliance | The key is stored in the permission-protected local `secrets.json`; provider configuration stores only a reference |
 
+:::info Already using cloud compute?
+If you've signed in and bound official cloud compute, you can **skip this page** and go straight to [Your First Conversation](./05-first-conversation.md). Come back anytime to add more providers.
+:::
+
 ## What is an API Key?
 
 An API Key is like a "key" to access AI services. Each AI provider (such as OpenAI, Anthropic, DeepSeek, etc.) offers API services — you need to register on their website, obtain an API Key, and then enter it in DesireCore so it can call the corresponding AI models.
@@ -33,6 +37,10 @@ Calls made with your own API key are billed by the corresponding provider. Offic
 
 <!-- Screenshot placeholder: Configure API Key (configure-api-key.png) -->
 
+:::note Key Security
+Your API Key is stored only in the local file `~/.desirecore/secrets.json` (file permission `600`, readable only by the current user). It is never uploaded to DesireCore servers or any third party.
+:::
+
 ## Provider API Key Guides
 
 DesireCore supports over 20 AI providers. Below are instructions for the most commonly used ones.