Fix Control UI i18n tooltip placeholders

Summary:
- Render the Sessions active filter tooltip with the configured minute count instead of a literal N.
- Update all Control UI locale bundles and i18n translation memory rows to preserve the {count} placeholder.
- Add a placeholder parity guard to the Control UI i18n check with regression coverage.

Verification:
- pnpm ui:i18n:check
- pnpm test src/scripts/control-ui-i18n.test.ts ui/src/ui/views/sessions.test.ts
- git diff --check
- Testbox exact-head pnpm check:changed passed on prior rebased head 1333aac90b before latest main churn.
- GitHub CI on fd2068c378 only failed the pre-existing unrelated checks-node-core-fast timeout in src/auto-reply/reply/followup-delivery.test.ts:176, also present on recent main runs b31c001a2b and e5f5989aa9.

src/scripts/control-ui-i18n.test.ts

@@ -0,0 +1,35 @@
+import { describe, expect, it } from "vitest";
+import { findPlaceholderMismatches } from "../../scripts/control-ui-i18n.ts";
+
+describe("control-ui-i18n placeholder validation", () => {
+  it("reports missing and extra placeholders by key", () => {
+    const mismatches = findPlaceholderMismatches(
+      new Map([
+        ["sessionsView.activeTooltip", "Updated in the last {count} minutes."],
+        ["sessionsView.store", "Store: {path}"],
+        ["sessionsView.limitTooltip", "Max sessions to load."],
+      ]),
+      new Map([
+        ["sessionsView.activeTooltip", "Actualizadas en los últimos N minutos."],
+        ["sessionsView.store", "Almacén: {path}"],
+        ["sessionsView.limitTooltip", "Máximo {extra} de sesiones."],
+      ]),
+      "es",
+    );
+
+    expect(mismatches).toEqual([
+      {
+        key: "sessionsView.activeTooltip",
+        locale: "es",
+        sourcePlaceholders: ["count"],
+        translatedPlaceholders: [],
+      },
+      {
+        key: "sessionsView.limitTooltip",
+        locale: "es",
+        sourcePlaceholders: [],
+        translatedPlaceholders: ["extra"],
+      },
+    ]);
+  });
+});