feat(client): typed locale standard seat in the slot framework

Registrations declare a dictionary namespace (locale: NS) and the renderer
synthesizes a typed t prop for the entry's component from the installed
LocaleFace; the seat binding is re-derived per locale revision, so a language
switch hands out fresh t references and memoized consumers re-render through
ordinary shallow comparison. LocaleNamespaceMap is the declare-merge table
(namespace -> dictionary key union); TranslateNS<'ns'> is the
namespace-addressed translate type (namespace keys plus the shared common
vocabulary), carried by the t seat and by the locale service's typed bind.

LocaleService implements the face (lookup ns -> common -> zh -> key,
revision-carrying snapshots with subscriber isolation) and installs it
through the boot-once slots.installLocale seam, mirroring the renderer
install. The typed register(ns, {zh, en}) overload checks each dictionary
against the namespace's key union and requires every shipped locale, so a
missing or extra key and an unbalanced translation are compile errors.
Dictionary registration bumps the face revision without emitting
locale/change — the event now means exactly 'the active locale switched',
so registration-heavy boot cannot storm event listeners.

pnpm-lock.yaml

@@ -1130,6 +1130,9 @@ importers:
       '@deepseek-ai/dsh-client-connection':
         specifier: workspace:^
         version: link:../connection
+      '@deepseek-ai/dsh-client-locale':
+        specifier: workspace:^
+        version: link:../locale
       '@deepseek-ai/dsh-client-runtime':
         specifier: workspace:^
         version: link:../runtime
@@ -1291,6 +1294,9 @@ importers:
       '@deepseek-ai/dsh-agent':
         specifier: workspace:^
         version: link:../../core/agent
+      '@deepseek-ai/dsh-client-locale':
+        specifier: workspace:^
+        version: link:../locale
       '@deepseek-ai/dsh-invariants':
         specifier: workspace:^
         version: link:../../support/invariants
@@ -1377,6 +1383,9 @@ importers:
         specifier: ^2.0.0
         version: 2.1.1
     devDependencies:
+      '@deepseek-ai/dsh-client-locale':
+        specifier: workspace:^
+        version: link:../locale
       '@deepseek-ai/dsh-client-runtime':
         specifier: workspace:^
         version: link:../runtime