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/AdminApp.tsx

@@ -46,7 +46,6 @@ const OffersTemplates = lazy(() => import("./pages/OffersTemplates"));
 const Orders = lazy(() => import("./pages/Orders"));
 const OrderDetail = lazy(() => import("./pages/OrderDetail"));
 const Projects = lazy(() => import("./pages/Projects"));
-const ProjectCreate = lazy(() => import("./pages/ProjectCreate"));
 const ProjectDetail = lazy(() => import("./pages/ProjectDetail"));
 const Invoices = lazy(() => import("./pages/Invoices"));
 const InvoiceDetail = lazy(() => import("./pages/InvoiceDetail"));
@@ -104,7 +103,6 @@ export default function AdminApp() {
                 <Route path="orders" element={<Orders />} />
                 <Route path="orders/:id" element={<OrderDetail />} />
                 <Route path="projects" element={<Projects />} />
-                <Route path="projects/new" element={<ProjectCreate />} />
                 <Route path="projects/:id" element={<ProjectDetail />} />
                 <Route path="invoices" element={<Invoices />} />
                 <Route path="invoices/new" element={<InvoiceDetail />} />