fix(notices): keep the release modal up across the whole 4.x line

The 4.0.0 notice was scoped to a 4.0.x window on the assumption that each
release would bring its own entry. 4.1.0 shipped without one, so the modal
switched itself off and nothing took its place: the thank-you notice it
replaced is retired below 4.0.0, leaving a 4.1 install with no notice at all.

Hold it open to the 5.0.0 boundary instead. What it introduces is the 4.x
line, which is still what somebody arriving on 4.1 or 4.2 is meeting for the
first time, and a later major gets its own entry the way this one did.

server/src/systemNotices/registry.ts

@@ -106,11 +106,14 @@ export const SYSTEM_NOTICES: SystemNotice[] = [
     conditions: [{ kind: 'managed', is: false }],
     publishedAt: '2026-08-22T00:00:00Z',
     priority: 110,
-    // The 4.0.x window. The copy is about this release, so somebody arriving on
-    // 4.1 — or jumping 3.x straight to 4.2 — should get that release's notice
-    // instead of this one, not a summary of a version they skipped.
+    // The whole 4.x line. The copy is about what 4.0.0 brought, and that is still
+    // what somebody arriving anywhere on 4.x is being introduced to — the minor
+    // releases after it add to that picture rather than replace it. Held open to
+    // the 5.0.0 boundary (exclusive) so a 4.1/4.2 install is not left with no
+    // notice at all, which is what a per-release window did the moment 4.1.0
+    // shipped without an entry of its own.
     minVersion: '4.0.0',
-    maxVersion: '4.1.0',
+    maxVersion: '5.0.0',
   },
 
   // ── Thank-you + support the project — shown once per install AND once per upgrade ──

server/tests/unit/systemNotices/registry.test.ts

@@ -65,19 +65,21 @@ describe('registry integrity', () => {
     }
   });
 
-  it('the 4.0.0 release notice is confined to the 4.0.x line', () => {
+  it('the 4.0.0 release notice covers the whole 4.x line', () => {
     const release = SYSTEM_NOTICES.find(n => n.id === 'release-4-0-0');
     expect(release).toBeDefined();
-    // Its copy is about this release, so it must not greet somebody who skipped
-    // straight past it, and it must not run alongside the next release's notice.
+    // It must not greet somebody still on 3.x...
     expect(isNoticeVersionActive(release!, '3.4.1')).toBe(false);
     expect(isNoticeVersionActive(release!, '4.0.0')).toBe(true);
     expect(isNoticeVersionActive(release!, '4.0.7')).toBe(true);
-    // The upper bound is exclusive, so every 4.0.x patch still gets it.
-    expect(isNoticeVersionActive(release!, '4.0.9')).toBe(true);
     expect(isNoticeVersionActive(release!, '4.0.12')).toBe(true);
-    expect(isNoticeVersionActive(release!, '4.1.0')).toBe(false);
-    expect(isNoticeVersionActive(release!, '4.2.0')).toBe(false);
+    // ...and it stays up across the minors, so no 4.x install is left without a
+    // notice the way 4.1.0 was under the old per-release window.
+    expect(isNoticeVersionActive(release!, '4.1.0')).toBe(true);
+    expect(isNoticeVersionActive(release!, '4.2.0')).toBe(true);
+    expect(isNoticeVersionActive(release!, '4.9.9')).toBe(true);
+    // The upper bound is exclusive: 5.0.0 gets its own notice.
+    expect(isNoticeVersionActive(release!, '5.0.0')).toBe(false);
   });
 
   it('the thank-you notice hands over to the release modal at 4.0.0', () => {