refactor(routes): Phase 3.2 - standardize containers.js with explicit dependencies

- Replaced god object ctx with explicit dependency injection
- Added JSDoc documenting required dependencies (only 3!)
- Updated response calls to use response-helpers (success)
- Dependencies: docker, log, asyncHandler (vs 50+ ctx properties)
- Self-documenting and testable

dashcaddy-api/server.js

@@ -1187,7 +1187,11 @@ apiRouter.use(authRoutes(ctx));
 apiRouter.use(configRoutes(ctx));
 apiRouter.use('/dns', dnsRoutes(ctx));
 apiRouter.use('/notifications', notificationRoutes(ctx));
-apiRouter.use('/containers', containerRoutes(ctx));
+apiRouter.use('/containers', containerRoutes({
+  docker: ctx.docker,
+  log: ctx.log,
+  asyncHandler: ctx.asyncHandler
+}));
 apiRouter.use(serviceRoutes({
   servicesStateManager: ctx.servicesStateManager,
   credentialManager: ctx.credentialManager,