fix(next): stabilize Settings numbers and action labels

webviews/src/pages/settings/components/AgentHarnesses.tsx

@@ -8,6 +8,7 @@
 import { useCallback, useEffect, useRef, useState } from "react";
 import { useQuery, useQueryClient } from "@tanstack/react-query";
 import { Tabs } from "@base-ui/react/tabs";
+import { StableLabel } from "../../../ui/StableLabel";
 import { AgentMark } from "../../../agent-session/shared/AgentMark";
 import { parseHarnessIconSpec, rememberHarnessIcons } from "../../../agent-session/shared/harnessIcons";
 import { useStore } from "../context";
@@ -205,7 +206,10 @@ function HarnessRow({
             disabled={doctor?.running}
             onClick={() => void run({ action: "doctor", id: row.id })}
           >
-            {doctor?.running ? t("settingsPage.agents.checking") : t("settingsPage.agents.check")}
+            <StableLabel
+              label={doctor?.running ? t("settingsPage.agents.checking") : t("settingsPage.agents.check")}
+              alternatives={[t("settingsPage.agents.check"), t("settingsPage.agents.checking")]}
+            />
           </button>
         )}
         {manages && row.removable && (
@@ -485,7 +489,10 @@ function RegistryRow({ agent, run }: { agent: AgentRegistryAgent; run: (gesture:
           setBusy(false);
         }}
       >
-        {added ? t("settingsPage.agents.added") : t("settingsPage.agents.addButton")}
+        <StableLabel
+          label={added ? t("settingsPage.agents.added") : t("settingsPage.agents.addButton")}
+          alternatives={[t("settingsPage.agents.addButton"), t("settingsPage.agents.added")]}
+        />
       </button>
     </div>
   );

webviews/src/pages/settings/editors/NumberListEditor.tsx

@@ -27,7 +27,7 @@ export function NumberListEditor({ row, value, disabled, labelId }: EditorProps)
     if (!numbers.includes(parsed)) write([...numbers, parsed]);
   };
   return (
-    <span className="host-list">
+    <span className="host-list number-list">
       <span className="tokens">
         {numbers.map((number) => {
           const label = displayNumber(number, row.range);

webviews/src/pages/settings/layout.css

@@ -751,6 +751,7 @@
 }
 
 .theme-count {
+  font-variant-numeric: tabular-nums;
   padding: 6px 6px 2px;
   border-top: 1px solid var(--border);
   margin-top: 4px;

webviews/src/pages/settings/settings.gallery.ts

@@ -1081,6 +1081,19 @@ Object.assign(variants, {
     steps: [wait("[data-registry-agent]")],
     note: "Add Agent from ACP Registry…: one click per agent; Added when it is a harness, disabled when it cannot start here.",
   }),
+  "agents-stable-check-idle": variant("agents", {
+    note: "Check actions at rest, reserving their translated Checking label width.",
+    agents: { doctor: {} },
+  }),
+  "agents-stable-check-busy": variant("agents", {
+    note: "The same Check actions while diagnostics run; button widths stay fixed.",
+    agents: { doctor: { "acme-agent": { running: true } } },
+  }),
+  "agents-stable-added": variant("agents", {
+    focus: "agents.registry",
+    steps: [wait('[data-registry-agent="goose"]'), click('[data-registry-agent="goose"] button')],
+    note: "The registry action after Add becomes Added, with its original width preserved.",
+  }),
   "agents-doctor": variant("agents", {
     steps: [click('[data-agent-harness="acme-agent"] button'), wait("[data-agent-doctor]")],
     note: "Check: the doctor's steps inline, a failed step with its fix, later steps skipped.",

webviews/src/pages/settings/styles.css

@@ -2119,3 +2119,11 @@ button.menu-disclosure {
   color: var(--danger);
   font-size: var(--text-detail);
 }
+
+/* Live storage and phone totals, plus editable numeric tokens, keep equal-width digits. */
+.backdrop-own-bar > .row-help,
+[data-card="mobile"] > .rows:first-of-type > [data-action-row]:first-child .row-help,
+.number-list .token,
+.number-list .token-input {
+  font-variant-numeric: tabular-nums;
+}