Add custom AI provider support and improve qBittorrent auth

Introduces support for custom OpenAI-compatible AI providers with configurable base URLs, including UI, backend validation, and connection testing. Enhances qBittorrent integration to support HTTP Basic Auth for reverse proxies, adds detailed debug logging, and updates documentation for both features. Also improves login page description logic and AI prompt generation for recommendations.

src/app/api/bookdate/config/route.ts

@@ -39,13 +39,13 @@ async function getConfig(req: AuthenticatedRequest) {
 async function saveConfig(req: AuthenticatedRequest) {
   try {
     const body = await req.json();
-    const { provider, apiKey, model, libraryScope, customPrompt, isEnabled } = body;
+    const { provider, apiKey, model, baseUrl, libraryScope, customPrompt, isEnabled } = body;
 
     // Check if config exists
     const existingConfig = await prisma.bookDateConfig.findFirst();
 
-    // Validation - API key only required for new configs
-    if (!existingConfig && !apiKey) {
+    // Validation - API key only required for new configs (except custom provider)
+    if (!existingConfig && !apiKey && provider !== 'custom') {
       return NextResponse.json(
         { error: 'API key is required for initial setup' },
         { status: 400 }
@@ -59,13 +59,39 @@ async function saveConfig(req: AuthenticatedRequest) {
       );
     }
 
-    if (!['openai', 'claude'].includes(provider)) {
+    if (!['openai', 'claude', 'custom'].includes(provider)) {
       return NextResponse.json(
-        { error: 'Invalid provider. Must be "openai" or "claude"' },
+        { error: 'Invalid provider. Must be "openai", "claude", or "custom"' },
         { status: 400 }
       );
     }
 
+    // Custom provider requires baseUrl
+    if (provider === 'custom') {
+      if (!baseUrl) {
+        return NextResponse.json(
+          { error: 'Base URL is required for custom provider' },
+          { status: 400 }
+        );
+      }
+
+      // Validate URL format
+      try {
+        const parsed = new URL(baseUrl);
+        if (parsed.protocol !== 'http:' && parsed.protocol !== 'https:') {
+          return NextResponse.json(
+            { error: 'Invalid base URL. Must use http:// or https://' },
+            { status: 400 }
+          );
+        }
+      } catch {
+        return NextResponse.json(
+          { error: 'Invalid base URL format' },
+          { status: 400 }
+        );
+      }
+    }
+
     // Determine which API key to use
     let encryptedApiKeyToUse: string;
 
@@ -73,13 +99,17 @@ async function saveConfig(req: AuthenticatedRequest) {
       // New API key provided - encrypt it
       const encryptionService = getEncryptionService();
       encryptedApiKeyToUse = encryptionService.encrypt(apiKey);
+    } else if (provider === 'custom' && !apiKey && !existingConfig) {
+      // Custom provider with no API key (local model) - encrypt empty string
+      const encryptionService = getEncryptionService();
+      encryptedApiKeyToUse = encryptionService.encrypt('');
     } else if (existingConfig) {
       // No new API key, use existing one
       encryptedApiKeyToUse = existingConfig.apiKey;
     } else {
-      // This shouldn't happen due to validation above, but just in case
+      // API key required for OpenAI/Claude
       return NextResponse.json(
-        { error: 'API key is required for new configuration' },
+        { error: 'API key is required' },
         { status: 400 }
       );
     }
@@ -100,6 +130,13 @@ async function saveConfig(req: AuthenticatedRequest) {
         updateData.apiKey = encryptedApiKeyToUse;
       }
 
+      // Update or clear baseUrl based on provider
+      if (provider === 'custom') {
+        updateData.baseUrl = baseUrl;
+      } else {
+        updateData.baseUrl = null; // Clear baseUrl when switching away from custom
+      }
+
       config = await prisma.bookDateConfig.update({
         where: { id: existingConfig.id },
         data: updateData,
@@ -111,6 +148,7 @@ async function saveConfig(req: AuthenticatedRequest) {
         data: {
           provider,
           model,
+          baseUrl: provider === 'custom' ? baseUrl : null,
           libraryScope: 'full', // Default value for backwards compatibility
           customPrompt: null,
           isEnabled: isEnabled !== undefined ? isEnabled : true,