feat: finish demo — port demo-monolith cleanup, separate UI and API containers

Frontend
- Bring spring-angular-ui back under version control with the Angular 22 +
  Material UI from demo-monolith; stop committing the built static/ folder
- Serve the UI from nginx, which proxies /api to the backend so the JWT
  cookie works on a single origin, and falls back to index.html for routes

Backend
- Add PUT /api/users/{id}/roles (admin only) that keeps at least one admin
  and does not let an admin drop their own admin role
- Tighten security: read tutorials publicly, change them only when logged
  in, users/roles API for admins only; hide password hashes in JSON
- Remove unused Settings and Test endpoints, DTO mappers, commented code
- Flyway V2 aligns the schema with the entities; Hibernate now runs with
  ddl-auto: validate
- JWT lifetime matches the 24h cookie; fix the cookie name typo
- Keep CORS only for calling the API directly (ng serve without proxy)

Docker
- Backend Dockerfile: Gradle build + JRE runtime with layer caching,
  non-root user and healthcheck; add .dockerignore
- UI Dockerfile: Node 24 build + nginx with healthcheck
- docker-compose runs its own Postgres, starts services in health order
  and always rebuilds images

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

spring-angular-ui/src/app/app.module.ts

@@ -2,30 +2,32 @@ import { NgModule } from '@angular/core';
 import { BrowserModule } from '@angular/platform-browser';
 
 import { AppRoutingModule } from './app-routing.module';
-import {FormsModule, ReactiveFormsModule} from '@angular/forms';
+import {FormsModule} from '@angular/forms';
 
 
 import { AppComponent } from './app.component';
 import { TutorialsListComponent } from './components/tutorials-list/tutorials-list.component';
 import { TutorialDetailsComponent } from './components/tutorial-details/tutorial-details.component';
 import { AddTutorialComponent } from './components/add-tutorial/add-tutorial.component';
-import { LoginComponent } from './components/login/login.component';
 import { RegisterComponent } from './components/register/register.component';
 import { HomeComponent } from './components/home/home.component';
 import { ProfileComponent } from './components/profile/profile.component';
 import { BoardAdminComponent } from './components/board-admin/board-admin.component';
-import { BoardModeratorComponent } from './components/board-moderator/board-moderator.component';
-import { BoardUserComponent } from './components/board-user/board-user.component';
 
-import { authInterceptorProviders } from './helpers/auth.interceptor';
-import {provideHttpClient, withInterceptorsFromDi} from "@angular/common/http";
+import {provideHttpClient, withXhr} from "@angular/common/http";
 import {provideAnimationsAsync} from "@angular/platform-browser/animations/async";
 import {MatToolbar} from "@angular/material/toolbar";
-import {MatAnchor, MatButton} from "@angular/material/button";
+import {MatButtonModule} from "@angular/material/button";
+import {MatCardModule} from "@angular/material/card";
+import {MatInputModule} from "@angular/material/input";
+import {MatListModule} from "@angular/material/list";
 import {MatIcon} from "@angular/material/icon";
-import {MatChipGrid, MatChipInput, MatChipListbox, MatChipOption, MatChipRow} from "@angular/material/chips";
-import {MatAutocomplete, MatAutocompleteTrigger, MatOption} from "@angular/material/autocomplete";
-import {MatFormField} from "@angular/material/form-field";
+import {MatMenu, MatMenuItem, MatMenuTrigger} from "@angular/material/menu";
+import {MatDivider} from "@angular/material/divider";
+import {MatPaginatorModule} from "@angular/material/paginator";
+import {MatSortModule} from "@angular/material/sort";
+import {MatTableModule} from "@angular/material/table";
+import {MatTooltipModule} from "@angular/material/tooltip";
 
 
 
@@ -39,9 +41,7 @@ import {MatFormField} from "@angular/material/form-field";
     RegisterComponent,
     HomeComponent,
     ProfileComponent,
-    BoardAdminComponent,
-    BoardModeratorComponent,
-    BoardUserComponent
+    BoardAdminComponent
 
   ],
   bootstrap: [AppComponent],
@@ -49,23 +49,22 @@ import {MatFormField} from "@angular/material/form-field";
     BrowserModule,
     AppRoutingModule,
     FormsModule,
-    LoginComponent,
     MatToolbar,
-    MatButton,
+    MatButtonModule,
+    MatCardModule,
+    MatInputModule,
+    MatListModule,
     MatIcon,
-    MatAnchor,
-    MatChipGrid,
-    MatChipRow,
-    MatChipInput,
-    MatAutocompleteTrigger,
-    MatAutocomplete,
-    MatOption,
-    MatFormField,
-    MatChipListbox,
-    MatChipOption,
-    ReactiveFormsModule
+    MatMenu,
+    MatMenuItem,
+    MatMenuTrigger,
+    MatDivider,
+    MatTableModule,
+    MatSortModule,
+    MatPaginatorModule,
+    MatTooltipModule
   ],
-  providers: [authInterceptorProviders, provideHttpClient(withInterceptorsFromDi()), provideAnimationsAsync()] })
+  providers: [provideHttpClient(withXhr()), provideAnimationsAsync()] })
 
 
 export class AppModule { }