Show PR numbers without the # and make header buttons icon-only

PR badges in the sidebar rows, hover card, and right-sidebar PR tab now
show the number alone. The Scripts and Open-in-editor header buttons drop
their labels and gain a min height so they keep the same size icon-only.

packages/app/src/git/pull-request-panel/tab-label.test.ts

@@ -2,11 +2,11 @@ import { describe, expect, it } from "vitest";
 import { formatPrTabLabel } from "./tab-label";
 
 describe("formatPrTabLabel", () => {
-  it("returns #<number> when a pull request number is present", () => {
-    expect(formatPrTabLabel(42)).toBe("#42");
+  it("returns the number when a pull request number is present", () => {
+    expect(formatPrTabLabel(42)).toBe("42");
   });
 
-  it("returns #— fallback when the pull request number is null", () => {
-    expect(formatPrTabLabel(null)).toBe("#—");
+  it("returns the — fallback when the pull request number is null", () => {
+    expect(formatPrTabLabel(null)).toBe("—");
   });
 });

packages/app/src/git/pull-request-panel/tab-label.ts

@@ -1,3 +1,3 @@
 export function formatPrTabLabel(prNumber: number | null): string {
-  return prNumber === null ? "#—" : `#${prNumber}`;
+  return prNumber === null ? "—" : `${prNumber}`;
 }