Account menu + Settings (change password); per-tree home person; full-width tree

- Sidebar bottom-left now shows the signed-in user; clicking opens a menu with
  Settings and Sign out. New /settings page: account info + change password
  (POST /auth/change-password, re-verifies current password). Export/restore/
  delete are stubbed there for the next pass.
- Per-tree default/home person: tree.home_person_id (migration) + TreeUpdate/
  Read; the tree and family views open focused on it; the person page gets a
  "Set as default" control and "Default person" badge. Cleared if that person
  is deleted. Complements the account-level "this is me" link.
- Tree visualization now fills the content area (AppShell drops the max-width
  column on the /tree route); other pages stay centered.
- Audit records are coerced JSON-safe (UUIDs/enums), so PATCHing UUID fields
  like home_person_id audits cleanly.

50 backend tests pass; migration up/down verified; frontend builds.

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

frontend/lib/api/schema.d.ts

@@ -140,6 +140,23 @@ export interface paths {
         patch?: never;
         trace?: never;
     };
+    "/api/v1/auth/change-password": {
+        parameters: {
+            query?: never;
+            header?: never;
+            path?: never;
+            cookie?: never;
+        };
+        get?: never;
+        put?: never;
+        /** Change Password */
+        post: operations["change_password_api_v1_auth_change_password_post"];
+        delete?: never;
+        options?: never;
+        head?: never;
+        patch?: never;
+        trace?: never;
+    };
     "/api/v1/users/me": {
         parameters: {
             query?: never;
@@ -998,6 +1015,13 @@ export interface components {
          * @enum {string}
          */
         ParentChildQualifier: "biological" | "adoptive" | "step" | "foster" | "donor" | "guardian";
+        /** PasswordChange */
+        PasswordChange: {
+            /** Current Password */
+            current_password: string;
+            /** New Password */
+            new_password: string;
+        };
         /** PasswordResetConfirm */
         PasswordResetConfirm: {
             /** Token */
@@ -1253,6 +1277,8 @@ export interface components {
              * Format: uuid
              */
             owner_id: string;
+            /** Home Person Id */
+            home_person_id?: string | null;
             /**
              * Created At
              * Format: date-time
@@ -1266,6 +1292,8 @@ export interface components {
             /** Description */
             description?: string | null;
             visibility?: components["schemas"]["TreeVisibility"] | null;
+            /** Home Person Id */
+            home_person_id?: string | null;
         };
         /**
          * TreeVisibility
@@ -1545,6 +1573,37 @@ export interface operations {
             };
         };
     };
+    change_password_api_v1_auth_change_password_post: {
+        parameters: {
+            query?: never;
+            header?: never;
+            path?: never;
+            cookie?: never;
+        };
+        requestBody: {
+            content: {
+                "application/json": components["schemas"]["PasswordChange"];
+            };
+        };
+        responses: {
+            /** @description Successful Response */
+            204: {
+                headers: {
+                    [name: string]: unknown;
+                };
+                content?: never;
+            };
+            /** @description Validation Error */
+            422: {
+                headers: {
+                    [name: string]: unknown;
+                };
+                content: {
+                    "application/json": components["schemas"]["HTTPValidationError"];
+                };
+            };
+        };
+    };
     read_me_api_v1_users_me_get: {
         parameters: {
             query?: never;