Alternate names (maiden/married), self-person link, deletion integrity

Names (the genealogy standard: maiden name primary, married/alias as typed
alternates):
- Name model already supported multiple typed names; expose full CRUD —
  NameCreate/Read/Update schemas, name_service (one-primary invariant,
  promote-on-delete), nested /persons/{id}/names routes.
- Person page gains a Names card: add/edit/delete + "make primary", with a
  curated name_type dropdown (birth/maiden, married, alias, nickname, …).

Self-person ("who am I"):
- users.self_person_id FK (use_alter for the users<->persons<->trees cycle)
  + migration; PATCH /users/me/self-person; "This is me" / "This is you"
  on the person page. Soft-deleting the linked person clears it.

Deletion integrity (fixes the broken tree view):
- delete_person now soft-deletes the relationships touching the person, so no
  dangling edges remain; family-chart also filters links to missing people.
- Optional cascade=true recursively deletes descendants (GEDCOM cleanup);
  the person page asks "only this person" vs "with all descendants".
- DELETE returns {deleted: n}.

Family view surfaces "Not connected to anyone" so dangling people aren't lost.

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

frontend/app/trees/[id]/tree/page.tsx

@@ -104,6 +104,11 @@ export default function TreePage() {
     if (status !== "ready" || mode === "fan" || !containerRef.current) return;
     let cancelled = false;
     (async () => {
+      // Only link to people that still exist — a soft-deleted person leaves
+      // dangling relationship rows, and family-chart breaks on an id with no
+      // matching datum. Filter them out so a deletion never blanks the tree.
+      const alive = new Set(people.map((pp) => pp.id));
+      const keep = (ids: string[]) => ids.filter((id) => alive.has(id));
       const data = people.map((pp) => {
         const [fn, ln] = splitName(pp.primary_name);
         return {
@@ -114,7 +119,11 @@ export default function TreePage() {
             birthday: years.get(pp.id) ?? "",
             gender: pp.gender === "female" ? "F" : "M",
           },
-          rels: { spouses: partnersOf(pp.id), parents: parentsOf(pp.id), children: childrenOf(pp.id) },
+          rels: {
+            spouses: keep(partnersOf(pp.id)),
+            parents: keep(parentsOf(pp.id)),
+            children: keep(childrenOf(pp.id)),
+          },
         };
       });
       const f3 = await import("family-chart");