feat: multi-cluster management with pool-based load balancing

- Add ClusterPool entity for grouping clusters into named pools
- Support 3 deployment modes: manual cluster, pool load-balanced, default fallback
- Pool strategies: least-apps (fewest deployed apps) and round-robin
- Add pool CRUD API endpoints (admin) and public pool listing
- Frontend deploy page: 3-mode cluster selector (Default/Manual/Pool)
- Frontend app detail: shows assigned cluster and pool info
- Admin pools management page with cluster selection and strategy picker
- Application entity extended with poolId field

backend/src/clusters/clusters.controller.ts

@@ -12,6 +12,7 @@ import { AuthGuard } from '@nestjs/passport';
 import { ApiTags, ApiOperation, ApiBearerAuth } from '@nestjs/swagger';
 import { ClustersService } from './clusters.service';
 import { CreateClusterDto, UpdateClusterDto } from './dto/cluster.dto';
+import { CreateClusterPoolDto, UpdateClusterPoolDto } from './dto/cluster-pool.dto';
 import { RolesGuard } from '../common/guards/roles.guard';
 import { Roles } from '../common/decorators/roles.decorator';
 import { UserRole } from '../common/enums';
@@ -20,44 +21,103 @@ import { UserRole } from '../common/enums';
 @ApiBearerAuth()
 @Controller('clusters')
 @UseGuards(AuthGuard('jwt'), RolesGuard)
-@Roles(UserRole.ADMIN)
 export class ClustersController {
   constructor(private readonly clustersService: ClustersService) {}
 
+  // ─── Public endpoints (any authenticated user) ────────────────────
+
+  @Get('public')
+  @ApiOperation({ summary: 'List available clusters (public info, no kubeconfig)' })
+  async findAllPublic() {
+    return this.clustersService.findAllPublic();
+  }
+
+  @Get('pools/public')
+  @ApiOperation({ summary: 'List active cluster pools with resolved cluster names' })
+  async findAllPoolsPublic() {
+    return this.clustersService.findAllPoolsPublic();
+  }
+
+  // ─── Cluster admin endpoints ──────────────────────────────────────
+
   @Post()
+  @Roles(UserRole.ADMIN)
   @ApiOperation({ summary: 'Register a new Kubernetes cluster (Admin only)' })
   async create(@Body() dto: CreateClusterDto) {
     return this.clustersService.create(dto);
   }
 
   @Get()
+  @Roles(UserRole.ADMIN)
   @ApiOperation({ summary: 'List all clusters (Admin only)' })
   async findAll() {
     return this.clustersService.findAll();
   }
 
   @Get(':id')
+  @Roles(UserRole.ADMIN)
   @ApiOperation({ summary: 'Get cluster details (Admin only)' })
   async findOne(@Param('id') id: string) {
     return this.clustersService.findOne(id);
   }
 
   @Patch(':id')
+  @Roles(UserRole.ADMIN)
   @ApiOperation({ summary: 'Update cluster configuration (Admin only)' })
   async update(@Param('id') id: string, @Body() dto: UpdateClusterDto) {
     return this.clustersService.update(id, dto);
   }
 
   @Post(':id/test')
+  @Roles(UserRole.ADMIN)
   @ApiOperation({ summary: 'Test connectivity to a registered cluster (Admin only)' })
   async testConnection(@Param('id') id: string) {
     return this.clustersService.testClusterById(id);
   }
 
   @Delete(':id')
+  @Roles(UserRole.ADMIN)
   @ApiOperation({ summary: 'Remove a cluster (Admin only)' })
   async delete(@Param('id') id: string) {
     await this.clustersService.delete(id);
     return { message: 'Cluster deleted' };
   }
+
+  // ─── Cluster Pool admin endpoints ─────────────────────────────────
+
+  @Post('pools')
+  @Roles(UserRole.ADMIN)
+  @ApiOperation({ summary: 'Create a cluster pool for load balancing (Admin only)' })
+  async createPool(@Body() dto: CreateClusterPoolDto) {
+    return this.clustersService.createPool(dto);
+  }
+
+  @Get('pools')
+  @Roles(UserRole.ADMIN)
+  @ApiOperation({ summary: 'List all cluster pools (Admin only)' })
+  async findAllPools() {
+    return this.clustersService.findAllPools();
+  }
+
+  @Get('pools/:id')
+  @Roles(UserRole.ADMIN)
+  @ApiOperation({ summary: 'Get cluster pool details (Admin only)' })
+  async findOnePool(@Param('id') id: string) {
+    return this.clustersService.findOnePool(id);
+  }
+
+  @Patch('pools/:id')
+  @Roles(UserRole.ADMIN)
+  @ApiOperation({ summary: 'Update cluster pool (Admin only)' })
+  async updatePool(@Param('id') id: string, @Body() dto: UpdateClusterPoolDto) {
+    return this.clustersService.updatePool(id, dto);
+  }
+
+  @Delete('pools/:id')
+  @Roles(UserRole.ADMIN)
+  @ApiOperation({ summary: 'Delete a cluster pool (Admin only)' })
+  async deletePool(@Param('id') id: string) {
+    await this.clustersService.deletePool(id);
+    return { message: 'Cluster pool deleted' };
+  }
 }