Add top-level members list, primary member on account, member move, combined create flows

- GET /v1/members with search across all members (includes account name)
- POST /members/:id/move with optional accountId (creates new account if omitted)
- primary_member_id on account table, auto-set when first member added
- isMinor flag on member create (manual override when no DOB provided)
- Account search now includes member names
- New account form includes primary contact fields, auto-generates name
- Members page in sidebar with global search

packages/backend/src/db/migrations/meta/_journal.json

@@ -57,6 +57,13 @@
       "when": 1774662300000,
       "tag": "0007_accounts_lookups",
       "breakpoints": true
+    },
+    {
+      "idx": 8,
+      "version": "7",
+      "when": 1774702800000,
+      "tag": "0008_member_primary_account",
+      "breakpoints": true
     }
   ]
 }