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-theme/README.md

@@ -2,11 +2,11 @@
 
 English | [中文](README.zh.md)
 
-Theme plugin: ThemeService over the --dsw-* token base stylesheets (static scale + alias semantic layers); apply(id) toggles the `body[data-ds-dark-theme]` attribute, so theme switches are pure CSS cascade. Contract: api-contracts v3 §8.
+Theme plugin: ThemeService over the --dsw-* token base stylesheets (static scale + alias semantic layers). The service owns the theme preference (`light`/`dark`/`system`, persisted under `dsh.theme`), resolves `system` through `prefers-color-scheme`, and publishes immutable `ThemeSnapshot`s on the `theme/change` event; it never touches the DOM — ui-layout's presenter applies the resolved snapshot (`body[data-ds-dark-theme]` + inline alias tokens). Contract: api-contracts v3 §8.
 
 ## Model Experience
 
-None, as the theme service toggles browser CSS; nothing here reaches a model request.
+None, as the theme service manages a browser preference; nothing here reaches a model request.
 
 #### KV Cache effect
 
@@ -14,6 +14,5 @@ None; this package neither assembles nor sends a provider request.
 
 ## Known Limitations and Deferred Work
 
-- **No theme-switch control ships in P-I** — the service surface (register/apply/current) is complete but no UI owner mounts a toggle; switching happens programmatically.
 - **Third-party themes are a surface, not a product** — registering one means overriding same-named alias variables; no validation exists that an override set is complete.
 - **The token sheets are the sole color authority** — values absent from cssdesign (for example the design's #4176E6 tab blue) are deliberately not appended; the nearest semantic token wins (arbitrated 2026-07-22).