feat: add analytics tracking to VShare WebView

Add custom User-Agent and source parameter to track V2er app traffic
to VShare page for analytics purposes.

Changes:
- Set custom User-Agent: "Mozilla/5.0... V2er-Android/{version}"
- Add source parameter to URL: "?theme={theme}&source=v2er-android"
- Add getAppVersion() method to retrieve app version for User-Agent

This enables VShare page to:
1. Identify traffic from V2er Android app via User-Agent header
2. Track app version distribution
3. Filter analytics by source parameter

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

Author: graycreate

app/src/main/java/me/ghui/v2er/module/vshare/VshareWebActivity.java

@@ -103,13 +103,10 @@ protected void init() {
 
         setupWebView();
 
-        // Compute URL with theme parameter based on current app theme
+        // Compute URL with theme and source parameters for analytics tracking
         String url = VSHARE_BASE_URL;
-        if (DarkModelUtils.isDarkMode()) {
-            url += "?theme=dark";
-        } else {
-            url += "?theme=light";
-        }
+        String themeParam = DarkModelUtils.isDarkMode() ? "dark" : "light";
+        url += "?theme=" + themeParam + "&source=v2er-android";
         mWebView.loadUrl(url);
     }
 
@@ -143,6 +140,12 @@ private void setupWebView() {
 
         WebSettings settings = mWebView.getSettings();
 
+        // Set custom User-Agent for analytics tracking
+        String defaultUserAgent = settings.getUserAgentString();
+        String appVersion = getAppVersion();
+        String customUserAgent = defaultUserAgent + " V2er-Android/" + appVersion;
+        settings.setUserAgentString(customUserAgent);
+
         // Enable JavaScript
         settings.setJavaScriptEnabled(true);
 
@@ -273,6 +276,18 @@ private int getStatusBarHeight() {
         return result;
     }
 
+    /**
+     * Get app version name for User-Agent tracking
+     */
+    private String getAppVersion() {
+        try {
+            return getPackageManager().getPackageInfo(getPackageName(), 0).versionName;
+        } catch (Exception e) {
+            Log.e(TAG, "Failed to get app version", e);
+            return "unknown";
+        }
+    }
+
     /**
      * Handle URL loading for WebView
      * Returns true if the URL was handled externally, false if WebView should load it