Add Backstage catalog files for all components

Add backstage.yml files to enable Backstage integration:
- System definition at root level
- Component definitions for catalog service, frontend, and database
- API definition for catalog REST endpoints
- Proper component relationships and dependencies

Co-authored-by: Ona <no-reply@ona.com>

Author: loujaybee

backend/catalog/backstage.yml

@@ -0,0 +1,50 @@
+apiVersion: backstage.io/v1alpha1
+kind: Component
+metadata:
+  name: catalog-service
+  description: Catalog service for Gitpod Flix
+  tags:
+    - nodejs
+    - express
+    - typescript
+    - api
+  annotations:
+    github.com/project-slug: gitpod-samples/gitpodflix-demo
+spec:
+  type: service
+  lifecycle: production
+  owner: team-platform
+  system: gitpodflix
+  providesApis:
+    - catalog-api
+  dependsOn:
+    - component:database-service
+---
+apiVersion: backstage.io/v1alpha1
+kind: API
+metadata:
+  name: catalog-api
+  description: REST API for movie catalog operations
+spec:
+  type: openapi
+  lifecycle: production
+  owner: team-platform
+  system: gitpodflix
+  definition: |
+    openapi: 3.0.0
+    info:
+      title: Catalog API
+      version: 1.0.0
+    paths:
+      /api/movies:
+        get:
+          summary: Get all movies
+      /api/search:
+        get:
+          summary: Search movies with filters
+      /api/suggestions:
+        get:
+          summary: Get search suggestions
+      /health:
+        get:
+          summary: Service health check

backstage.yml

@@ -0,0 +1,22 @@
+apiVersion: backstage.io/v1alpha1
+kind: System
+metadata:
+  name: gitpodflix
+  description: Modern streaming platform demo showcasing full-stack development in Gitpod
+  tags:
+    - streaming
+    - demo
+    - full-stack
+  annotations:
+    github.com/project-slug: gitpod-samples/gitpodflix-demo
+spec:
+  owner: team-platform
+  domain: media
+---
+apiVersion: backstage.io/v1alpha1
+kind: Domain
+metadata:
+  name: media
+  description: Media and streaming services domain
+spec:
+  owner: team-platform

database/backstage.yml

@@ -0,0 +1,16 @@
+apiVersion: backstage.io/v1alpha1
+kind: Component
+metadata:
+  name: database-service
+  description: PostgreSQL database with full-text search for movie catalog
+  tags:
+    - postgresql
+    - database
+    - docker
+  annotations:
+    github.com/project-slug: gitpod-samples/gitpodflix-demo
+spec:
+  type: database
+  lifecycle: production
+  owner: team-platform
+  system: gitpodflix

frontend/backstage.yml

@@ -0,0 +1,22 @@
+apiVersion: backstage.io/v1alpha1
+kind: Component
+metadata:
+  name: frontend
+  description: React frontend application for Gitpod Flix streaming platform
+  tags:
+    - react
+    - typescript
+    - vite
+    - tailwindcss
+    - frontend
+  annotations:
+    github.com/project-slug: gitpod-samples/gitpodflix-demo
+spec:
+  type: website
+  lifecycle: production
+  owner: team-platform
+  system: gitpodflix
+  consumesApis:
+    - catalog-api
+  dependsOn:
+    - component:catalog-service