Enhance install-claude-code.sh with provider switching and coding-helper

Major Features Added:
- Provider Switching: Detect current API provider (Anthropic/Z.AI) and offer switching
- API Key Update: Easy update of existing API keys without reinstalling
- Z.AI Coding-Helper Integration: Optional installation of @z_ai/coding-helper

Provider Detection:
- Detects Z.AI by checking for dashscope-intl.aliyuncs.com URL
- Detects Anthropic by checking for anthropic.com or ANTHROPIC_API_KEY
- Shows current provider and API key (masked) when script runs

Provider Switching Options:
1. Switch to Z.AI (GLM models: glm-4.5-air, glm-4.7)
2. Switch to Anthropic (Official Claude models)
3. Update API key only (keep current provider)
4. Skip configuration

Z.AI Coding-Helper Addons:
- Interactive wizard for easy setup
- Multi-tool management (Claude Code, OpenCode, Crush, Factory Droid)
- MCP service configuration
- API key management for Global and China plans
- Bilingual interface (English/Chinese)
- Automatic tool detection and installation
- Configuration backup and sync

Configuration Management:
- Automatic backup of settings.json before changes
- Smart merging of existing configurations
- Proper model switching (GLM ↔ Claude models)
- Base URL configuration for Z.AI

Enhanced Banner:
- Shows all three main features (Z.AI, Provider Switching, Coding-Helper)

README Updates:
- Documented new features in install-claude-code.sh section
- Added provider switching workflow explanation
- Listed coding-helper addon features

README.md

@@ -180,26 +180,45 @@ curl -fsSL https://github.rommark.dev/admin/SuperCharged-Claude-Code-Upgrade/raw
 ```
 
 ### install-claude-code.sh - Claude Code + Z.AI Installer
-Installs Claude Code and configures Z.AI GLM models.
+Installs Claude Code and configures Z.AI GLM models or Anthropic API.
+
+**New Features:**
+- 🔀 **Provider Switching** - Switch between Anthropic and Z.AI APIs
+- 🔑 **API Key Update** - Update existing API keys easily
+- 🧩 **Coding-Helper Addons** - Optional Z.AI coding-helper installation
 
 | Option | Description |
 |--------|-------------|
-| `--auto` (default) | Automated installation with API key prompt |
+| `--auto` (default) | Automated installation with provider selection |
 | `--manual` | Show manual installation steps only |
 | `--skip-install` | Skip Claude Code install, configure API only |
 
 **One-liners:**
 ```bash
-# Auto install with API prompt
+# Auto install with provider selection
 curl -fsSL https://github.rommark.dev/admin/SuperCharged-Claude-Code-Upgrade/raw/main/install-claude-code.sh | bash
 
 # Show manual instructions
 curl -fsSL https://github.rommark.dev/admin/SuperCharged-Claude-Code-Upgrade/raw/main/install-claude-code.sh | bash -s -- --manual
 
-# Configure API only
+# Configure API only (skip Claude Code install)
 curl -fsSL https://github.rommark.dev/admin/SuperCharged-Claude-Code-Upgrade/raw/main/install-claude-code.sh | bash -s -- --skip-install
 ```
 
+**Provider Switching:**
+If Claude Code is already installed, the script will:
+1. Detect your current API provider (Anthropic or Z.AI)
+2. Offer to switch between providers
+3. Allow you to update your API key
+4. Optionally install Z.AI coding-helper addons
+
+**Z.AI Coding-Helper Features:**
+- Interactive wizard for easy setup
+- Multi-tool management (Claude Code, OpenCode, etc.)
+- MCP service configuration
+- API key management for Global and China plans
+- Bilingual interface (English/Chinese)
+
 ---
 
 ## 🔧 Claude Code Installation Details