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.

packages/client/ui-settings-general/src/invariant.ts

@@ -0,0 +1,32 @@
+/**
+ * Package-owned invariant companion for `@deepseek-ai/dsh-client-ui-settings-general`.
+ * @module @deepseek-ai/dsh-client-ui-settings-general/invariant
+ */
+
+/* jscpd:ignore-start */
+import type { Context } from 'cordis'
+import type { InvariantInstaller } from '@deepseek-ai/dsh-invariants'
+
+const PACKAGE_NAME = '@deepseek-ai/dsh-client-ui-settings-general'
+
+/** Cordis companion plugin name. */
+export const name = 'client-ui-settings-general-invariant'
+/** Service required before the companion can reserve package ownership. */
+export const inject = ['invariants']
+
+/**
+ * No runtime invariant: a copy-owning registrant contributing chrome content
+ * and the General section into shell-declared slots — it emits no cordis
+ * events and owns no cross-plugin mutable relation; slot conflicts already
+ * fail loud in the slot core at load time.
+ */
+const install: InvariantInstaller = () => {}
+
+/**
+ * Register this package's invariant companion.
+ * @param ctx - Cordis context carrying the invariant service.
+ * @returns the installed registration's disposer after setup succeeds.
+ */
+export const apply = (ctx: Context): Promise<() => void> =>
+  Promise.resolve(ctx.invariants.register(PACKAGE_NAME, install))
+/* jscpd:ignore-end */