Refactor arr routes: explicit dependency injection

- Updated all arr route modules to use destructured dependencies
- Added JSDoc comments for factory functions
- Replaced ctx. references with direct parameter access
- Updated arr/index.js to extract and pass explicit dependencies
- Maintained backward compatibility with context pattern
- All files pass syntax validation

Files refactored:
- routes/arr/detect.js
- routes/arr/credentials.js
- routes/arr/config.js (579 lines)
- routes/arr/smart-connect.js
- routes/arr/plex.js
- routes/arr/helpers.js
- routes/arr/index.js (orchestrator)

dashcaddy-api/routes/arr/index.js

@@ -1,14 +1,34 @@
 const express = require('express');
 
+/**
+ * Arr routes aggregator
+ * Assembles all arr sub-routes with their dependencies
+ * @param {Object} ctx - Application context (for backward compatibility)
+ * @returns {express.Router}
+ */
 module.exports = function(ctx) {
   const router = express.Router();
-  const helpers = require('./helpers')(ctx);
 
-  router.use(require('./detect')(ctx, helpers));
-  router.use(require('./credentials')(ctx, helpers));
-  router.use(require('./config')(ctx, helpers));
-  router.use(require('./smart-connect')(ctx, helpers));
-  router.use(require('./plex')(ctx, helpers));
+  // Extract dependencies from context
+  const deps = {
+    docker: ctx.docker,
+    credentialManager: ctx.credentialManager,
+    servicesStateManager: ctx.servicesStateManager,
+    fetchT: ctx.fetchT,
+    asyncHandler: ctx.asyncHandler,
+    errorResponse: ctx.errorResponse,
+    log: ctx.log
+  };
+
+  // Initialize helpers with dependencies
+  const helpers = require('./helpers')(deps);
+
+  // Mount sub-routes with explicit dependencies
+  router.use(require('./detect')({ ...deps, helpers }));
+  router.use(require('./credentials')({ ...deps, helpers }));
+  router.use(require('./config')({ ...deps, helpers }));
+  router.use(require('./smart-connect')({ ...deps, helpers }));
+  router.use(require('./plex')({ ...deps, helpers }));
 
   return router;
 };