fix: remove manual project creation, smart sequence release, received-invoices schema fix

- Remove ProjectCreate page, POST /projects endpoint, and next-number endpoint
- Projects can only be created through orders (shared numbering sequence)
- Remove dead CreateProjectSchema and createProject service function
- Delete 'order' row from number_sequences (unused; code uses 'shared')
- Smart sequence release: decrement last_number only when deleting the highest number
- Fix received-invoices stats referencing non-existent is_deleted and amount_czk columns
- Update deploy instructions in CLAUDE.md (npm install, prisma migrate deploy)

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/admin/pages/Projects.tsx

@@ -160,22 +160,6 @@ export default function Projects() {
             )}
           </p>
         </div>
-        {hasPermission("projects.create") && (
-          <Link to="/projects/new" className="admin-btn admin-btn-primary">
-            <svg
-              width="20"
-              height="20"
-              viewBox="0 0 24 24"
-              fill="none"
-              stroke="currentColor"
-              strokeWidth="2"
-            >
-              <line x1="12" y1="5" x2="12" y2="19" />
-              <line x1="5" y1="12" x2="19" y2="12" />
-            </svg>
-            Nový projekt
-          </Link>
-        )}
       </motion.div>
 
       <motion.div