feat(claude-binary): implement robust version selector with enhanced binary detection

This commit provides a comprehensive solution to Claude binary detection issues
by implementing a user-friendly version selector UI and improving the binary
discovery logic. It addresses all concerns raised in multiple PRs and comments.

Changes:
- Add ClaudeVersionSelector component for selecting from multiple installations
- Update ClaudeBinaryDialog to use version selector instead of manual path input
- Fix unused variable warning in production builds (claude.rs:442)
- Improve select_best_installation to handle production build restrictions
- Add listClaudeInstallations API endpoint to fetch all available installations
- Make Claude version indicator clickable to navigate to Settings
- Move Claude installation selector to General tab in Settings (per user request)
- Enhance dialog UX with loading states and clear installation instructions
- Add Radix UI radio-group dependency for version selector

Fixes:
- Production build warning about unused claude_path variable
- Version detection failures in production builds due to process restrictions
- Poor UX when Claude binary is not found (now shows helpful dialog)
- Inability to easily switch between multiple Claude installations

This implementation takes inspiration from:
- PR #3: Version selector dropdown approach (preferred by users)
- PR #4: Binary detection improvements and path validation
- PR #39: Additional detection methods and error handling
- Commit 5a29f9a: Shared claude binary detection module architecture

Addresses feedback from:
- getAsterisk/claudia#4 (comment): User preference for dropdown selector
- Production build restrictions that prevent version detection
- Need for better error handling when Claude is not installed

The solution provides a seamless experience whether Claude is installed via:
- npm/yarn/bun global installation
- nvm-managed Node.js versions
- Homebrew on macOS
- System-wide installation
- Local user installation (~/.local/bin, etc.)

Refs: #3, #4, #39, 5a29f9a

src/lib/api.ts

@@ -78,6 +78,18 @@ export interface FileEntry {
   extension?: string;
 }
 
+/**
+ * Represents a Claude installation found on the system
+ */
+export interface ClaudeInstallation {
+  /** Full path to the Claude binary */
+  path: string;
+  /** Version string if available */
+  version?: string;
+  /** Source of discovery (e.g., "nvm", "system", "homebrew", "which") */
+  source: string;
+}
+
 // Sandbox API types
 export interface SandboxProfile {
   id?: number;
@@ -1908,4 +1920,17 @@ export const api = {
       throw error;
     }
   },
+
+  /**
+   * List all available Claude installations on the system
+   * @returns Promise resolving to an array of Claude installations
+   */
+  async listClaudeInstallations(): Promise<ClaudeInstallation[]> {
+    try {
+      return await invoke<ClaudeInstallation[]>("list_claude_installations");
+    } catch (error) {
+      console.error("Failed to list Claude installations:", error);
+      throw error;
+    }
+  },
 };