fix(storage,workspace): post-review hardening

Review findings applied across the group:
- storage hub: stale disposers no longer remove a successor registration;
  the package now default-exports the Storage service class per the
  service-package export shape.
- json backend: failed publishes roll back the authoritative memory state
  (a rejected write can no longer resurface via get() or ride the next
  publish); close() drains in-flight writes and blocks in-flight opens;
  double-open rejects as a plain caller error instead of malformed-medium.
- sqlite backend: loadAll builds records on a null prototype (__proto__
  keys round-trip instead of polluting), user_version is stamped only
  after the schema is fully created, and corrupt record JSON rejects as
  malformed-medium instead of a bare SyntaxError.
- domain form: writes persist before mutating authoritative memory or
  emitting; DomainChanged is a put/deleted discriminated union.
- workspace: attach/detach idempotence decided on the write chain (stale
  snapshots no longer short-circuit), create() requires a directory, and
  startup fails loud on duplicate stored paths.

Eleven regression tests pin the fixed behaviors.

packages/storage/storage-sqlite/src/schema.ts

@@ -81,10 +81,6 @@ function configureDatabase(db: DatabaseSync, path: string, journalMode: JournalM
       `storage database at "${path}" has schema version ${onDisk}, incompatible with this build (${STORAGE_SQLITE_SCHEMA_VERSION})`,
     )
   }
-  if (onDisk === 0) {
-    // Stamp fresh databases.
-    db.exec(`PRAGMA user_version = ${STORAGE_SQLITE_SCHEMA_VERSION}`)
-  }
   db.exec(`
     CREATE TABLE IF NOT EXISTS units (
       name    TEXT PRIMARY KEY,
@@ -97,6 +93,12 @@ function configureDatabase(db: DatabaseSync, path: string, journalMode: JournalM
       value TEXT NOT NULL
     ) STRICT
   `)
+  if (onDisk === 0) {
+    // Stamp fresh databases LAST: the stamp asserts the layout is complete,
+    // so a failure above must leave the medium unstamped (a re-open after
+    // the obstruction is cleared retries materialization from scratch).
+    db.exec(`PRAGMA user_version = ${STORAGE_SQLITE_SCHEMA_VERSION}`)
+  }
 }
 
 /**