Tree Cleanup tool: bulk fixes with preview → approve

A new per-tree Cleanup page (and cleanup_service + endpoints), each fix
preview-first per the propose-then-approve rule:

- Mark deceased by birth year: lists people born ≤ a cutoff (default 1930) not
  already deceased; apply sets is_living=false for the ones you keep checked.
- Set sex from a source GEDCOM: upload the source .ged (it carries SEX); matches
  by name and proposes sex only where it's missing — far more accurate than
  guessing from first names. Review, then apply.
- Names that look broken: flags date-in-surname / date-in-given / no-surname /
  packed given names, with inline editable given+surname; fix the checked ones.

No migration (uses existing columns). 55 backend tests pass (preview+apply for
all three); frontend builds.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

frontend/components/app-sidebar.tsx

@@ -9,6 +9,7 @@ import {
   LogOut,
   Network,
   Settings,
+  Sparkles,
   Users,
 } from "lucide-react";
 import Link from "next/link";
@@ -128,6 +129,12 @@ export function AppSidebar({ onNavigate }: { onNavigate?: () => void }) {
             icon={ArrowDownUp}
             active={pathname.startsWith(`/trees/${treeId}/gedcom`)}
           />
+          <Item
+            href={`/trees/${treeId}/cleanup`}
+            label="Cleanup"
+            icon={Sparkles}
+            active={pathname.startsWith(`/trees/${treeId}/cleanup`)}
+          />
           <Item
             href={`/trees/${treeId}/recovery`}
             label="Recovery"