refactor(gui): copy-free settings shell; ui-settings-general owns ownerless copy

The shell is now a pure composition face: no dictionaries, no locale
dependency, and three new chrome content seats (settings.trigger /
settings.header / settings.close) whose slot content also carries the
accessible names (trigger text, dialog aria-labelledby, visually hidden
close label). ui-settings-general returns as the owner of copy that
belongs to no single feature: chrome content, the General section with
its item slot, and the settings dictionaries. Slot types split homes —
trigger/header/close/section live in the shell contract; the
settings.general.item entry moves to the locale package (the common
dependency of every item registrant), with ui-theme consuming it
through a re-export seam; the verbatim duplicate merges are gone and
the dependency graph is a clean DAG.

tsconfig.client.json

@@ -39,6 +39,7 @@
     { "path": "./packages/client/ui-trajectory" },
     { "path": "./packages/client/ui-theme" },
     { "path": "./packages/client/ui-settings" },
+    { "path": "./packages/client/ui-settings-general" },
     { "path": "./packages/client/ui-models" },
     { "path": "./packages/client/locale" },
     { "path": "./packages/client/web" },