Merge remote-tracking branch 'origin/master' into worktree/i18n-complete-non-readme

# Conflicts:
#	packages/client/i18n/README.md
#	packages/client/locale/README.i18n.yaml
#	packages/client/locale/README.zh.md
#	packages/client/ui-layout/README.md
#	packages/client/ui-theme/README.md

packages/client/ui-slots/src/deferred.ts

@@ -0,0 +1,66 @@
+/**
+ * Declaration-aware registration deferral: the shared timing machinery for
+ * registering into a slot whose declaring entry activates in unconstrained
+ * order (dshClient.inject edges never sequence apply). Presence is judged on
+ * the LEDGER, not a local flag — after an HMR collapse re-declares the slot,
+ * the cascade has already removed the entry while the local disposer went
+ * stale, and a flag guard would block the re-registration.
+ */
+
+/** Minimal registry face the deferral reads (SlotsService satisfies it). */
+export interface DeferralRegistry {
+  /** Declared spec lookup (undefined = not declared yet). */
+  spec(name: string): unknown
+  /** Current entries of the slot (component identity is the presence judge). */
+  entries(name: string): readonly { component: unknown }[]
+  /** Subscribe to the slot's ledger changes; returns the unsubscriber. */
+  subscribe(name: string, listener: () => void): () => void
+}
+
+/** Handle over one deferred registration. */
+export interface DeferredRegistration {
+  /**
+   * Drop the current registration (stale disposers are harmless no-ops) and
+   * immediately re-attempt — the refresh path for registrants whose options
+   * carry localized text.
+   */
+  refresh(): void
+  /** Unsubscribe and unregister (idempotent through the slot core). */
+  dispose(): void
+}
+
+/**
+ * Register into `name` as soon as its declaration is on the ledger, and
+ * re-register whenever the declaration reappears after a collapse.
+ * @param registry - the slot registry face.
+ * @param name - target slot name.
+ * @param component - the component whose ledger presence marks "registered".
+ * @param register - performs the actual registration; returns its disposer.
+ * @returns the deferral handle (dispose in the owning effect's disposer).
+ */
+export function deferRegistration(
+  registry: DeferralRegistry,
+  name: string,
+  component: unknown,
+  register: () => () => void,
+): DeferredRegistration {
+  let dispose: (() => void) | undefined
+  const tryRegister = (): void => {
+    if (registry.spec(name) === undefined) return
+    if (registry.entries(name).some(e => e.component === component)) return
+    dispose = register()
+  }
+  const unsubscribe = registry.subscribe(name, () => { tryRegister() })
+  tryRegister()
+  return {
+    refresh() {
+      dispose?.()
+      dispose = undefined
+      tryRegister()
+    },
+    dispose() {
+      unsubscribe()
+      dispose?.()
+    },
+  }
+}

packages/client/ui-slots/src/index.ts

@@ -18,6 +18,7 @@ import type { BoundActions, HandleOf, PropsStore, SnapshotSelectorHook, StoreDec
 
 export * from './store.ts'
 export * from './renderer.ts'
+export * from './deferred.ts'
 
 /** Slot contract table. Owners extend via declaration merging; entries are {@link SlotEntryDef}. */
 export interface SlotMap {}