feat: pre-registrant management and invitation system

Admin interface to review, filter, and batch-invite the 95 pre-registrants
from Baby Ghosts. Accept-invitation page pre-fills their data and collects
circle, pronouns, motivation, contribution tier, and agreement before
creating their member record.

server/migrations/import-babyghosts-preregistrations.js

@@ -92,6 +92,19 @@ async function run() {
       }
     }
 
+    // Normalize: ensure all docs have status field for Mongoose model compatibility
+    if (!DRY_RUN) {
+      const normalized = await dest.updateMany(
+        { status: { $exists: false } },
+        { $set: { status: "pending" } },
+      );
+      if (normalized.modifiedCount > 0) {
+        console.log(
+          `\nNormalized ${normalized.modifiedCount} record(s) with missing status field.`,
+        );
+      }
+    }
+
     console.log("\n=== Summary ===");
     console.log(`  Inserted : ${inserted}`);
     console.log(`  Skipped  : ${skipped}`);