feat: unsplash api proxy (#6572)

.github/helm/affine/charts/graphql/templates/deployment.yaml

@@ -159,6 +159,11 @@ spec:
               secretKeyRef:
                 name: "{{ .Values.app.copilot.secretName }}"
                 key: falSecret
+          - name: COPILOT_UNSPLASH_API_KEY
+            valueFrom:
+              secretKeyRef:
+                name: "{{ .Values.app.copilot.secretName }}"
+                key: unsplashSecret
           {{ end }}
           {{ if .Values.app.oauth.google.enabled }}
           - name: OAUTH_GOOGLE_ENABLED