chore(release): v1.4.15

Bumps version to 1.4.15 and adds the corresponding CHANGELOG entry
covering backup completeness, achievements UI, onboarding tour,
doctor-report v2, auto-deploy on GHCR push, empty-states sweep,
notification + integration status UI, AI hallucination guardrails,
mobile UX fixes, and the BD-Zielbereich percentage fix.

Includes the formatting drift left over by the v1.4.15 development
phases (Prettier sweep on touched files) and a typecheck fix in
`dashboard-layout.test.ts` so `pnpm typecheck`, `pnpm lint`,
`pnpm format:check`, `pnpm test`, and `pnpm test:integration` all
pass green on the release tag.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/lib/integrations/__tests__/admin-alert.test.ts

@@ -58,9 +58,7 @@ describe("formatAdminAlertPayload — moodLog transient", () => {
       subjectLabel: "marc@example.com",
     });
     expect(out.title).toBe("moodLog sync failing for marc@example.com");
-    expect(out.message).toContain(
-      "Action: investigate the upstream service.",
-    );
+    expect(out.message).toContain("Action: investigate the upstream service.");
     expect(out.message).toContain("(http_502)");
   });
 });