feat(server): impl storage runtime (#15181)

#### PR Dependency Tree


* **PR #15181** 👈

This tree was auto-generated by
[Charcoal](https://github.com/danerwilliams/charcoal)

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

* **New Features**
* Added an additional storage backend option: asset-pack based storage
(provider for avatar, blob, and copilot).
* Introduced a dedicated storage runtime with provider capability
reporting and expanded object operations (put/head/get/list/delete),
including presigned and multipart flows where supported.
* Cloudflare R2 `jurisdiction` now uses an explicit default when
omitted.
* **Bug Fixes**
  * Broadened avatar access to allow both fs and asset-pack providers.
* Improved workspace blob upload completion validation and handling when
stored objects are missing or mismatched.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

packages/backend/server/src/app.module.ts

@@ -25,7 +25,6 @@ import { MetricsModule } from './base/metrics';
 import { MutexModule } from './base/mutex';
 import { PrismaModule } from './base/prisma';
 import { RedisModule } from './base/redis';
-import { StorageProviderModule } from './base/storage';
 import { RateLimiterModule } from './base/throttler';
 import { WebSocketModule } from './base/websocket';
 import { AccessTokenModule } from './core/access-token';
@@ -47,6 +46,7 @@ import { RealtimeModule } from './core/realtime';
 import { SelfhostModule } from './core/selfhost';
 import { StaticFileModule } from './core/static-files';
 import { StorageModule } from './core/storage';
+import { StorageRuntimeModule } from './core/storage-runtime';
 import { SyncModule } from './core/sync';
 import { TelemetryModule } from './core/telemetry';
 import { UserModule } from './core/user';
@@ -114,7 +114,6 @@ export const FunctionalityModules = [
   MutexModule,
   MetricsModule,
   RateLimiterModule,
-  StorageProviderModule,
   HelpersModule,
   ErrorModule,
   WebSocketModule,
@@ -122,6 +121,7 @@ export const FunctionalityModules = [
   RealtimeModule,
   ModelsModule,
   BackendRuntimeModule,
+  StorageRuntimeModule,
   ScheduleModule.forRoot(),
   MonitorModule,
 ];