refactor(desktop): move Settings → Usage into a features/usage slice

Extract the Usage settings surface out of the frozen legacy renderer zone into a
feature slice `src/renderer/features/usage/` (ports + services-context + ui), so
net-new Usage work (the #2015/#4164 pricing tab) is no longer blocked by the
tooltip and the read-only pricing tab).

- `features/usage/` owns the surface: narrow `UsageServices` ports
  (`loadUsageStats`, `updateUsageSettings` — `UsageSettings` in and out, never the
  whole `AppSettings`); a persistent `UsageFeatureScope` holding the single tagged
  `{ range, value }` snapshot + reload ticket + Host-generation invalidation +
  load-failure toast; and a disposable `UsageSettingsView`.
- `settings/usage-settings-page.tsx` is a thin legacy shim (`UsageScopeMount` +
  `UsageSettingsPage`). `settings-surface.tsx` mounts the scope ABOVE its
  loading/error gate and passes a `host:epoch` `targetKey` as a prop; the scope
  clears and fences in place on a target change (no React `key`). The Host-change
  handler also calls the scope's imperative `fenceTarget()` synchronously, so an
  in-flight old-Host load cannot land in the window before the re-render.
- Regenerate renderer-architecture.json and the astryx surface inventory.

Extraction-only; the Desktop adapter/composition wiring and the editable pricing
tab remain follow-ups. Refs #4425.

Generated-by: Claude Code

Author: liuxiaocs7

apps/desktop/renderer-architecture.json

@@ -181,7 +181,6 @@
     "src/renderer/settings/runtime-host-ssh-terminal-dialog.tsx",
     "src/renderer/settings/settings-error-copy.ts",
     "src/renderer/settings/settings-expandable-row.tsx",
-    "src/renderer/settings/settings-metric-card.tsx",
     "src/renderer/settings/settings-modal.tsx",
     "src/renderer/settings/settings-nav.ts",
     "src/renderer/settings/settings-request-authority.ts",
@@ -3891,17 +3890,6 @@
           "react": 1
         }
       },
-      "src/renderer/settings/settings-metric-card.tsx": {
-        "bridgePaths": {},
-        "environmentCapabilities": {},
-        "hookCalls": {},
-        "lifecycleMethods": {},
-        "unresolvedDependencies": 0,
-        "actionFactories": [],
-        "dependencyPaths": {
-          "@maka/ui": 1
-        }
-      },
       "src/renderer/settings/settings-modal.tsx": {
         "bridgePaths": {},
         "environmentCapabilities": {},
@@ -4085,11 +4073,11 @@
           "window.removeEventListener": 1
         },
         "hookCalls": {
-          "useEffect": 10,
+          "useEffect": 9,
           "useMediaQuery": 1,
           "useMountedRef": 1,
-          "useRef": 10,
-          "useState": 12,
+          "useRef": 8,
+          "useState": 11,
           "useToast": 1,
           "useUiLocale": 2
         },
@@ -4247,29 +4235,17 @@
         "bridgePaths": {},
         "environmentCapabilities": {},
         "hookCalls": {
-          "useActionGuard": 1,
-          "useOptimisticSettingsDraft": 1,
-          "useState": 1,
-          "useToast": 1,
           "useUiLocale": 1
         },
         "lifecycleMethods": {},
         "unresolvedDependencies": 0,
         "actionFactories": [],
         "dependencyPaths": {
-          "../../shared/runtime-host-identity.js": 1,
-          "../locales/settings-usage-copy": 1,
+          "../features/usage": 2,
           "./settings-error-copy": 1,
-          "./settings-metric-card": 1,
           "./settings-section": 1,
-          "./use-action-guard": 1,
-          "./use-optimistic-settings-draft": 1,
-          "@astryxdesign/core": 1,
           "@maka/core/settings": 1,
-          "@maka/core/ui-locale": 1,
-          "@maka/core/usage-ledger-merge": 1,
           "@maka/ui": 1,
-          "@maka/ui/icons": 1,
           "react": 1
         }
       },