docs: add installer environment variables documentation

docs/.vitepress/config.mts

@@ -35,6 +35,7 @@ const guideSidebar = [
       { text: 'Migrate to Vite+', link: '/guide/migrate' },
       { text: 'Installing Dependencies', link: '/guide/install' },
       { text: 'Environment', link: '/guide/env' },
+      { text: 'Installer Environment Variables', link: '/guide/installer-env-vars' },
       { text: 'Why Vite+', link: '/guide/why' },
     ],
   },

docs/guide/index.md

@@ -28,6 +28,8 @@ Alternatively, download and run [`vp-setup.exe`](https://setup.viteplus.dev).
 The `vp-setup.exe` is not yet code-signed. Your browser may show a warning when downloading. Click **"..."** → **"Keep"** → **"Keep anyway"** to proceed. If Windows Defender SmartScreen blocks the file when you run it, click **"More info"** → **"Run anyway"**.
 :::
 
+The installer scripts and `vp-setup.exe` read [environment variables](/guide/installer-env-vars) such as `VP_VERSION` and `VP_HOME`.
+
 After installation, open a new shell and run:
 
 ```bash

docs/guide/installer-env-vars.md

@@ -0,0 +1,195 @@
+# Installer Environment Variables
+
+The Vite+ installers (`vp-setup.exe`, `install.ps1`, and `install.sh`) and the installed `vp` CLI read the environment variables on this page.
+
+## Installation Variables
+
+These variables control the installer scripts and the standalone Windows installer (`vp-setup.exe`).
+
+### `VP_VERSION`
+
+- **Purpose**: Version to install
+- **Default**: `latest`
+- **CLI equivalent**: `--version`
+- **Example**:
+
+  ```bash
+  # Unix
+  curl -fsSL https://vite.plus | VP_VERSION=1.2.3 bash
+  ```
+
+  ```powershell
+  # PowerShell
+  $env:VP_VERSION = "1.2.3"; irm https://vite.plus/ps1 | iex
+  ```
+
+### `VP_HOME`
+
+- **Purpose**: Installation directory; the installed CLI reads the same variable as the Vite+ home directory (see [Environment](/guide/env))
+- **Default**: `~/.vite-plus` (Unix) or `%USERPROFILE%\.vite-plus` (Windows)
+- **CLI equivalent**: `--install-dir`
+- **Example**:
+
+  ```bash
+  # Unix
+  curl -fsSL https://vite.plus | VP_HOME=/opt/vite-plus bash
+  ```
+
+  ```powershell
+  # PowerShell
+  $env:VP_HOME = "D:\vite-plus"; irm https://vite.plus/ps1 | iex
+  ```
+
+### `NPM_CONFIG_REGISTRY`
+
+- **Purpose**: Custom npm registry URL
+- **Default**: `https://registry.npmjs.org`
+- **CLI equivalent**: `--registry`
+- **Example**:
+  ```bash
+  curl -fsSL https://vite.plus | NPM_CONFIG_REGISTRY=https://registry.npmmirror.com bash
+  ```
+
+### `VP_NODE_MANAGER`
+
+- **Purpose**: Control Node.js version manager setup during installation
+- **Values**: `yes` or `no`
+- **Default**: Auto-detected
+- **CLI equivalent**: `--no-node-manager` (inverted)
+- **Example**:
+  ```bash
+  # Skip Node.js manager setup in CI
+  curl -fsSL https://vite.plus | VP_NODE_MANAGER=no bash
+  ```
+
+### `VP_PR_VERSION`
+
+- **Purpose**: Install a preview build from a pull request or commit SHA
+- **Values**: PR number or commit SHA
+- **Default**: None
+- **Details**: [Global `vp` Preview](/guide/upgrade#global-vp-preview)
+
+### Development variables
+
+When developing Vite+ itself, `VP_LOCAL_TGZ` (path to a local `vite-plus.tgz`) and `VP_LOCAL_BINARY` (path to a local `vp` binary) feed the installer a local build. The installers also set `VP_INSTALL_STOP` themselves; do not set it manually.
+
+## Runtime Variables
+
+These variables configure the installed Vite+ CLI. `VP_HOME` (above) also applies at runtime.
+
+### `VP_NODE_DIST_MIRROR`
+
+- **Purpose**: Node.js distribution mirror URL
+- **Default**: `https://nodejs.org/dist`
+- **Details**: [Custom Node.js Mirror](/guide/env#custom-nodejs-mirror)
+
+### `VP_NODE_VERSION`
+
+- **Purpose**: Override Node.js version
+- **Default**: None (auto-detected)
+- **Example**:
+  ```bash
+  # Run a command with a specific Node.js version
+  VP_NODE_VERSION=22 vp env exec node -v
+  ```
+
+### `VP_NODE_SKIP_SIGNATURE_VERIFY`
+
+- **Purpose**: Skip PGP signature verification of Node.js downloads
+- **Values**: Any non-empty value
+- **Default**: None (verification enabled)
+- **Details**: [Node.js Signature Verification](/guide/env#nodejs-signature-verification)
+
+### `VP_SHELL`
+
+- **Purpose**: Specify the current shell
+- **Default**: Auto-detected
+- **Example**:
+  ```bash
+  VP_SHELL=bash vp env print
+  ```
+
+### `VP_BYPASS`
+
+- **Purpose**: Bypass the Vite+ shim and use the system tool
+- **Values**: `PATH`-style list of directories to bypass
+- **Default**: None
+- **Example**:
+  ```bash
+  VP_BYPASS=/usr/local/bin node -v
+  ```
+
+### Internal variables
+
+Vite+ sets additional `VP_*` variables during shim dispatch and shell integration (recursion guards, active-version records, wrapper flags); do not set them manually.
+
+## TLS/CA Configuration
+
+### `SSL_CERT_FILE` / `NODE_EXTRA_CA_CERTS`
+
+- **Purpose**: Path to PEM bundle of extra CA certificates (`NODE_EXTRA_CA_CERTS` is the Node.js convention)
+- **Default**: System trust store
+- **Example**:
+  ```bash
+  export SSL_CERT_FILE=/path/to/custom-ca.pem
+  ```
+
+### `VP_INSECURE_TLS`
+
+- **Purpose**: Disable HTTPS certificate verification
+- **Values**: Any non-empty value (`1`, `true`, `yes`)
+- **Default**: None (verification enabled)
+- **Warning**: Diagnostic escape hatch only; do not use in production
+- **Example**:
+  ```bash
+  VP_INSECURE_TLS=1 vp env install 22
+  ```
+
+## Logging and Debugging
+
+### `VITE_LOG`
+
+- **Purpose**: Log filter string for `tracing_subscriber`
+- **Default**: None
+- **Example**:
+  ```bash
+  VITE_LOG=debug vp dev
+  VITE_LOG=vite_task=trace vp build
+  ```
+
+### `VP_DEBUG_SHIM`
+
+- **Purpose**: Enable debug output for shim dispatch
+- **Values**: Any non-empty value
+- **Default**: None
+- **Example**:
+  ```bash
+  VP_DEBUG_SHIM=1 node -v
+  ```
+
+## Standard Environment Variables
+
+Vite+ also respects these standard environment variables:
+
+### `CI`
+
+- **Purpose**: Indicates running in CI environment
+- **Effect**: Enables silent mode (`--yes`) for installers
+
+### `NO_COLOR`
+
+- **Purpose**: Disable colored output
+- **Effect**: Disables ANSI color codes
+
+### `HOME` / `USERPROFILE`
+
+- **Purpose**: User home directory
+- **Effect**: Base for the default `~/.vite-plus` path
+
+## Precedence
+
+1. CLI flags (highest priority)
+2. Environment variables
+3. Default values (lowest priority)
+
+For example, `VP_VERSION=1.0.0 vp-setup.exe --version 2.0.0` installs version 2.0.0.