Code quality improvements from code review

- Add admin-only authorization for company and projects CRUD operations
- Create requireAccountId middleware to eliminate code duplication
- Standardize error handling (use next(error) consistently)
- Change error messages to Slovak language

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

Co-Authored-By: Claude <noreply@anthropic.com>

src/routes/company.routes.js

@@ -1,6 +1,7 @@
 import express from 'express';
 import * as companyController from '../controllers/company.controller.js';
 import { authenticate } from '../middlewares/auth/authMiddleware.js';
+import { requireAdmin } from '../middlewares/auth/roleMiddleware.js';
 import { validateBody, validateParams } from '../middlewares/security/validateInput.js';
 import { createCompanySchema, updateCompanySchema, createCompanyReminderSchema, updateCompanyReminderSchema } from '../validators/crm.validators.js';
 import { z } from 'zod';
@@ -39,24 +40,27 @@ router.get(
   companyController.getCompanyById
 );
 
-// Create new company
+// Create new company (admin only)
 router.post(
   '/',
+  requireAdmin,
   validateBody(createCompanySchema),
   companyController.createCompany
 );
 
-// Update company
+// Update company (admin only)
 router.patch(
   '/:companyId',
+  requireAdmin,
   validateParams(z.object({ companyId: z.string().uuid() })),
   validateBody(updateCompanySchema),
   companyController.updateCompany
 );
 
-// Delete company
+// Delete company (admin only)
 router.delete(
   '/:companyId',
+  requireAdmin,
   validateParams(z.object({ companyId: z.string().uuid() })),
   companyController.deleteCompany
 );
@@ -70,6 +74,7 @@ router.get(
 
 router.post(
   '/:companyId/notes',
+  requireAdmin,
   validateParams(z.object({ companyId: z.string().uuid() })),
   validateBody(z.object({
     content: z.string().min(1),
@@ -79,6 +84,7 @@ router.post(
 
 router.patch(
   '/:companyId/notes/:noteId',
+  requireAdmin,
   validateParams(z.object({
     companyId: z.string().uuid(),
     noteId: z.string().uuid()
@@ -91,6 +97,7 @@ router.patch(
 
 router.delete(
   '/:companyId/notes/:noteId',
+  requireAdmin,
   validateParams(z.object({
     companyId: z.string().uuid(),
     noteId: z.string().uuid()
@@ -107,6 +114,7 @@ router.get(
 
 router.post(
   '/:companyId/reminders',
+  requireAdmin,
   validateParams(z.object({ companyId: z.string().uuid() })),
   validateBody(createCompanyReminderSchema),
   companyController.createCompanyReminder
@@ -114,6 +122,7 @@ router.post(
 
 router.patch(
   '/:companyId/reminders/:reminderId',
+  requireAdmin,
   validateParams(z.object({
     companyId: z.string().uuid(),
     reminderId: z.string().uuid()
@@ -124,6 +133,7 @@ router.patch(
 
 router.delete(
   '/:companyId/reminders/:reminderId',
+  requireAdmin,
   validateParams(z.object({
     companyId: z.string().uuid(),
     reminderId: z.string().uuid()