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/Topbar.tsx

@@ -95,21 +95,28 @@ export const Topbar: React.FC<TopbarProps> = ({
     if (!versionStatus) return null;
     
     const statusContent = (
-      <div className="flex items-center space-x-2 text-xs">
-        <Circle
-          className={cn(
-            "h-3 w-3",
-            versionStatus.is_installed 
-              ? "fill-green-500 text-green-500" 
-              : "fill-red-500 text-red-500"
-          )}
-        />
-        <span>
-          {versionStatus.is_installed && versionStatus.version
-            ? `Claude Code ${versionStatus.version}`
-            : "Claude Code"}
-        </span>
-      </div>
+      <Button
+        variant="ghost"
+        size="sm"
+        className="h-auto py-1 px-2 hover:bg-accent"
+        onClick={onSettingsClick}
+      >
+        <div className="flex items-center space-x-2 text-xs">
+          <Circle
+            className={cn(
+              "h-3 w-3",
+              versionStatus.is_installed 
+                ? "fill-green-500 text-green-500" 
+                : "fill-red-500 text-red-500"
+            )}
+          />
+          <span>
+            {versionStatus.is_installed && versionStatus.version
+              ? `Claude Code ${versionStatus.version}`
+              : "Claude Code"}
+          </span>
+        </div>
+      </Button>
     );
     
     if (!versionStatus.is_installed) {
@@ -124,6 +131,14 @@ export const Topbar: React.FC<TopbarProps> = ({
                   {versionStatus.output}
                 </pre>
               </div>
+              <Button
+                variant="outline"
+                size="sm"
+                className="w-full"
+                onClick={onSettingsClick}
+              >
+                Select Claude Installation
+              </Button>
               <a
                 href="https://www.anthropic.com/claude-code"
                 target="_blank"