Enhance error handling and validation in agents and routes

- Added logging for empty responses in GeminiAgent and OpenRouterAgent to track potential session context issues.
- Refactored settings file path usage in OpenRouterAgent to use a constant for better maintainability.
- Improved error handling in SessionRoutes to log generator failures with detailed context.
- Implemented JSON parsing error handling in SettingsRoutes to manage corrupted settings files gracefully.
- Added validation for CLAUDE_MEM_OPENROUTER_MAX_CONTEXT_MESSAGES, CLAUDE_MEM_OPENROUTER_MAX_TOKENS, and CLAUDE_MEM_OPENROUTER_SITE_URL in SettingsRoutes to ensure valid configuration.

src/services/worker/http/routes/SettingsRoutes.ts

@@ -71,7 +71,16 @@ export class SettingsRoutes extends BaseRouteHandler {
 
     if (existsSync(settingsPath)) {
       const settingsData = readFileSync(settingsPath, 'utf-8');
-      settings = JSON.parse(settingsData);
+      try {
+        settings = JSON.parse(settingsData);
+      } catch (parseError) {
+        logger.error('SETTINGS', 'Failed to parse settings file', { settingsPath }, parseError as Error);
+        res.status(500).json({
+          success: false,
+          error: 'Settings file is corrupted. Delete ~/.claude-mem/settings.json to reset.'
+        });
+        return;
+      }
     }
 
     // Update all settings from request body
@@ -319,6 +328,31 @@ export class SettingsRoutes extends BaseRouteHandler {
       }
     }
 
+    // Validate CLAUDE_MEM_OPENROUTER_MAX_CONTEXT_MESSAGES
+    if (settings.CLAUDE_MEM_OPENROUTER_MAX_CONTEXT_MESSAGES) {
+      const count = parseInt(settings.CLAUDE_MEM_OPENROUTER_MAX_CONTEXT_MESSAGES, 10);
+      if (isNaN(count) || count < 1 || count > 100) {
+        return { valid: false, error: 'CLAUDE_MEM_OPENROUTER_MAX_CONTEXT_MESSAGES must be between 1 and 100' };
+      }
+    }
+
+    // Validate CLAUDE_MEM_OPENROUTER_MAX_TOKENS
+    if (settings.CLAUDE_MEM_OPENROUTER_MAX_TOKENS) {
+      const tokens = parseInt(settings.CLAUDE_MEM_OPENROUTER_MAX_TOKENS, 10);
+      if (isNaN(tokens) || tokens < 1000 || tokens > 1000000) {
+        return { valid: false, error: 'CLAUDE_MEM_OPENROUTER_MAX_TOKENS must be between 1000 and 1000000' };
+      }
+    }
+
+    // Validate CLAUDE_MEM_OPENROUTER_SITE_URL if provided
+    if (settings.CLAUDE_MEM_OPENROUTER_SITE_URL) {
+      try {
+        new URL(settings.CLAUDE_MEM_OPENROUTER_SITE_URL);
+      } catch {
+        return { valid: false, error: 'CLAUDE_MEM_OPENROUTER_SITE_URL must be a valid URL' };
+      }
+    }
+
     // Skip observation types validation - any type string is valid since modes define their own types
     // The database accepts any TEXT value, and mode-specific validation happens at parse time