feat(lifecycle): add billing lifecycle with auto-suspend/delete

- New AppLifecycleService with cron-based scanner (60s interval)
- State machine: ACTIVE → SUSPENDED → PENDING_DELETION → DELETED
- Auto-renew hourly plans from wallet
- Admin-configurable grace periods via PlatformSettings table
- New LifecycleController (GET/PATCH /lifecycle/settings)
- PlatformSetting entity for runtime admin config
- BillingService: calculateCostForApp, deductWallet
- Application entity: planId, billingCycle, lifecycleStatus, planExpiresAt
- New enums: AppLifecycleStatus, BillingCycle

backend/src/billing/billing.controller.ts

@@ -9,10 +9,14 @@ import {
   Query,
   UseGuards,
   Request,
+  BadRequestException,
+  Inject,
+  forwardRef,
 } from '@nestjs/common';
 import { AuthGuard } from '@nestjs/passport';
 import { ApiTags, ApiOperation, ApiBearerAuth } from '@nestjs/swagger';
 import { BillingService } from './billing.service';
+import { AppLifecycleService } from '../lifecycle/app-lifecycle.service';
 import {
   CreateServicePlanDto,
   UpdateServicePlanDto,
@@ -21,14 +25,18 @@ import {
 } from './dto/billing.dto';
 import { RolesGuard } from '../common/guards/roles.guard';
 import { Roles } from '../common/decorators/roles.decorator';
-import { UserRole } from '../common/enums';
+import { UserRole, BillingCycle, AppLifecycleStatus } from '../common/enums';
 
 @ApiTags('Billing')
 @ApiBearerAuth()
 @Controller('billing')
 @UseGuards(AuthGuard('jwt'), RolesGuard)
 export class BillingController {
-  constructor(private readonly billingService: BillingService) {}
+  constructor(
+    private readonly billingService: BillingService,
+    @Inject(forwardRef(() => AppLifecycleService))
+    private readonly lifecycleService: AppLifecycleService,
+  ) {}
 
   // ─── Service Plans (Admin) ────────────────────────────────────────
 
@@ -98,18 +106,49 @@ export class BillingController {
   }
 
   @Post('wallet/pay/:applicationId')
-  @ApiOperation({ summary: 'Pay for an application from wallet' })
+  @ApiOperation({ summary: 'Pay for an application plan from wallet — activates/renews the app' })
   async payForApplication(
     @Request() req: any,
     @Param('applicationId') applicationId: string,
-    @Body() body: { amount: number; cycle: string },
+    @Body() body: { planId: string; cycle: string },
   ) {
-    return this.billingService.deductWallet(
+    const cycle = body.cycle as BillingCycle;
+    if (!Object.values(BillingCycle).includes(cycle)) {
+      throw new BadRequestException(`Invalid billing cycle: ${body.cycle}`);
+    }
+
+    // Calculate cost
+    const plan = await this.billingService.findPlan(body.planId);
+    const costs = await this.billingService.calculateCost({
+      runtime: plan.runtime,
+      databaseType: 'none', // Will be refined per-app later
+      cpuLimit: '500m',
+      memoryLimit: '512Mi',
+      replicas: 1,
+    });
+
+    const amount = cycle === BillingCycle.HOURLY ? costs.hourly
+      : cycle === BillingCycle.MONTHLY ? costs.monthly
+      : costs.yearly;
+
+    // Deduct from wallet
+    const tx = await this.billingService.deductWallet(
       req.user.id,
-      body.amount,
-      `Payment for application (${body.cycle})`,
+      amount,
+      `Payment for app ${applicationId} (${cycle}) — plan: ${plan.name}`,
       applicationId,
     );
+
+    // Activate/reactivate the application
+    const app = await this.lifecycleService.activateApp(applicationId, cycle, body.planId);
+
+    return {
+      transaction: tx,
+      application: { id: app.id, name: app.name, lifecycleStatus: app.lifecycleStatus, planExpiresAt: app.planExpiresAt },
+      message: app.lifecycleStatus === AppLifecycleStatus.ACTIVE
+        ? `Application "${app.name}" activated until ${app.planExpiresAt?.toISOString()}`
+        : `Payment processed — application status: ${app.lifecycleStatus}`,
+    };
   }
 
   // ─── Payment Gateway ─────────────────────────────────────────────