build(eslint): focus-safe-disabled folds into button-primitive

Two rules looked at the same <button>: button-primitive refused a raw one
outside the control primitives, focus-safe-disabled refused a raw
`disabled` one everywhere but FocusSafeButton and AnchoredPopover. They are
one rule now, with the same reach: outside the primitives a raw button is
refused (a disabled one with the focus message); inside a primitive and in
a test only a raw `<button disabled>` is, and the two native-disabled owners
are named in the rule rather than in a config override. One override block,
one rule entry and two register rows go; the snapshot loses a config group.
focusSafe.contract.test.ts pins every case, the primitive and test ones new.

frontend/src/lib/focusSafe.contract.test.ts

@@ -2,16 +2,19 @@ import { describe, expect, it } from "vitest";
 
 import { eslint } from "./lintProbe.testkit";
 
-// `local/focus-safe-disabled` (eslint.config.js): a raw `<button disabled>` throws a focused keyboard
-// user to <body> the moment it turns disabled. ~60 were swept onto ui/FocusSafeButton; this pins that
-// the rule keeping a new one out actually fires.
-const RULE = "local/focus-safe-disabled";
-
+// `local/button-primitive`'s disabled check (eslint.config.js): a raw `<button disabled>` throws a
+// focused keyboard user to <body> the moment it turns disabled. ~60 were swept onto ui/FocusSafeButton;
+// this pins that the check keeping a new one out fires — also inside a control primitive and a test,
+// where the rest of the rule stands aside.
 async function hits(source: string, filePath = "src/components/__probe.tsx"): Promise<number> {
   const [result] = await eslint.lintText(source, { filePath });
-  return (result?.messages ?? []).filter((m) => m.ruleId === RULE).length;
+  return (result?.messages ?? []).filter(
+    (m) => m.ruleId === "local/button-primitive" && m.messageId === "disabled",
+  ).length;
 }
 
+const DISABLED = "export const D = (p: { d: boolean }) => <button disabled={p.d}>x</button>;\n";
+
 describe("a raw button that can be disabled", () => {
   it("is refused, statically or not", async () => {
     expect(
@@ -20,13 +23,15 @@ describe("a raw button that can be disabled", () => {
     expect(await hits("export const B = () => <button disabled>x</button>;\n")).toBe(1);
   });
 
-  it("leaves a raw button with no disabled, and the primitive, alone", async () => {
+  it("is refused inside a control primitive and in a test too", async () => {
+    expect(await hits(DISABLED, "src/components/ui/Button.tsx")).toBe(1);
+    // an existing test file: the project service admits only lintProbe.testkit's probe names
+    expect(await hits(DISABLED, "src/components/Feed.countStale.dom.test.tsx")).toBe(1);
+  });
+
+  it("leaves a raw button with no disabled, and the two native-disabled owners, alone", async () => {
     expect(await hits("export const C = () => <button onClick={() => {}}>x</button>;\n")).toBe(0);
-    expect(
-      await hits(
-        "export const D = (p: { d: boolean }) => <button disabled={p.d}>x</button>;\n",
-        "src/components/ui/FocusSafeButton.tsx",
-      ),
-    ).toBe(0);
+    expect(await hits(DISABLED, "src/components/ui/FocusSafeButton.tsx")).toBe(0);
+    expect(await hits(DISABLED, "src/components/ui/AnchoredPopover.tsx")).toBe(0);
   });
 });