feat(web): add workspace-aware session flow

packages/storage/storage/src/index.ts

@@ -15,6 +15,18 @@ export type { StorageErrorCode } from './error.ts'
 export { UNIT_NAME_RE } from './backend.ts'
 export type { StorageBackend, KvFacet, KvUnit, KvUnitDescriptor } from './backend.ts'
 
+/**
+ * Derive the Cordis lifecycle service that one named backend plugin provides.
+ * Domain-form providers inject these keys so activation cannot race backend
+ * registration even though callers continue resolving backends through the
+ * storage registry.
+ * @param name - Backend registry name.
+ * @returns the corresponding lifecycle-only service key.
+ */
+export function storageBackendServiceKey(name: string): string {
+  return `storage.backend.${name}`
+}
+
 declare module 'cordis' {
   interface Context {
     storage: Storage

packages/storage/storage/tests/registry.spec.ts

@@ -1,6 +1,6 @@
 import { describe, expect, it } from 'vitest'
 import { Context } from 'cordis'
-import Storage, { BackendRegistry } from '../src/index.ts'
+import Storage, { BackendRegistry, storageBackendServiceKey } from '../src/index.ts'
 import type { StorageBackend } from '../src/index.ts'
 
 const fakeBackend = (): StorageBackend => ({ close: async () => {} })
@@ -25,6 +25,11 @@ describe('BackendRegistry', () => {
 })
 
 describe('Storage service', () => {
+  it('derives stable lifecycle service keys for named backends', () => {
+    expect(storageBackendServiceKey('json')).toBe('storage.backend.json')
+    expect(storageBackendServiceKey('tenant-a')).toBe('storage.backend.tenant-a')
+  })
+
   it('mounts on the context and exposes registry plus form mounting', async () => {
     const ctx = new Context()
     await ctx.plugin(Storage)