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/components/Settings.tsx

@@ -20,10 +20,12 @@ import { Card } from "@/components/ui/card";
 import { Tabs, TabsList, TabsTrigger, TabsContent } from "@/components/ui/tabs";
 import { 
   api, 
-  type ClaudeSettings
+  type ClaudeSettings,
+  type ClaudeInstallation
 } from "@/lib/api";
 import { cn } from "@/lib/utils";
 import { Toast, ToastContainer } from "@/components/ui/toast";
+import { ClaudeVersionSelector } from "./ClaudeVersionSelector";
 
 interface SettingsProps {
   /**
@@ -69,12 +71,30 @@ export const Settings: React.FC<SettingsProps> = ({
   // Environment variables state
   const [envVars, setEnvVars] = useState<EnvironmentVariable[]>([]);
 
+  // Claude binary path state
+  const [currentBinaryPath, setCurrentBinaryPath] = useState<string | null>(null);
+  const [selectedInstallation, setSelectedInstallation] = useState<ClaudeInstallation | null>(null);
+  const [binaryPathChanged, setBinaryPathChanged] = useState(false);
+
 
   // Load settings on mount
   useEffect(() => {
     loadSettings();
+    loadClaudeBinaryPath();
   }, []);
 
+  /**
+   * Loads the current Claude binary path
+   */
+  const loadClaudeBinaryPath = async () => {
+    try {
+      const path = await api.getClaudeBinaryPath();
+      setCurrentBinaryPath(path);
+    } catch (err) {
+      console.error("Failed to load Claude binary path:", err);
+    }
+  };
+
   /**
    * Loads the current Claude settings
    */
@@ -159,6 +179,14 @@ export const Settings: React.FC<SettingsProps> = ({
 
       await api.saveClaudeSettings(updatedSettings);
       setSettings(updatedSettings);
+
+      // Save Claude binary path if changed
+      if (binaryPathChanged && selectedInstallation) {
+        await api.setClaudeBinaryPath(selectedInstallation.path);
+        setCurrentBinaryPath(selectedInstallation.path);
+        setBinaryPathChanged(false);
+      }
+
       setToast({ message: "Settings saved successfully!", type: "success" });
     } catch (err) {
       console.error("Failed to save settings:", err);
@@ -246,6 +274,13 @@ export const Settings: React.FC<SettingsProps> = ({
     setEnvVars(prev => prev.filter(envVar => envVar.id !== id));
   };
 
+  /**
+   * Handle Claude installation selection
+   */
+  const handleClaudeInstallationSelect = (installation: ClaudeInstallation) => {
+    setSelectedInstallation(installation);
+    setBinaryPathChanged(installation.path !== currentBinaryPath);
+  };
 
   return (
     <div className={cn("flex flex-col h-full bg-background text-foreground", className)}>
@@ -391,6 +426,25 @@ export const Settings: React.FC<SettingsProps> = ({
                         How long to retain chat transcripts locally (default: 30 days)
                       </p>
                     </div>
+                    
+                    {/* Claude Binary Path Selector */}
+                    <div className="space-y-4">
+                      <div>
+                        <Label className="text-sm font-medium mb-2 block">Claude Code Installation</Label>
+                        <p className="text-xs text-muted-foreground mb-4">
+                          Select which Claude Code installation to use
+                        </p>
+                      </div>
+                      <ClaudeVersionSelector
+                        selectedPath={currentBinaryPath}
+                        onSelect={handleClaudeInstallationSelect}
+                      />
+                      {binaryPathChanged && (
+                        <p className="text-xs text-amber-600 dark:text-amber-400">
+                          ⚠️ Claude binary path has been changed. Remember to save your settings.
+                        </p>
+                      )}
+                    </div>
                   </div>
                 </div>
               </Card>