feat: extend notification system with batch sender, bulk dialog, and logging

Add NotificationLog schema extensions (nullable userId, email, roundId,
projectId, batchId fields), batch notification sender service, and bulk
notification dialog UI. Include utility scripts for debugging and seeding.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

scripts/backfill-team-leads.ts

@@ -0,0 +1,78 @@
+/**
+ * Backfill TeamMember records for all projects that have a submittedByUserId
+ * but no corresponding TeamMember link.
+ *
+ * Usage: npx tsx scripts/backfill-team-leads.ts
+ *        Add --dry-run to preview without making changes.
+ */
+
+import { PrismaClient } from '@prisma/client'
+
+const prisma = new PrismaClient()
+const dryRun = process.argv.includes('--dry-run')
+
+async function main() {
+  console.log(dryRun ? '🔍 DRY RUN — no changes will be made\n' : '🚀 Backfilling team leads...\n')
+
+  // Find all projects with a submitter but no TeamMember link for that user
+  const projects = await prisma.project.findMany({
+    where: {
+      submittedByUserId: { not: null },
+    },
+    select: {
+      id: true,
+      title: true,
+      submittedByUserId: true,
+      teamMembers: {
+        select: { userId: true },
+      },
+    },
+  })
+
+  let created = 0
+  let alreadyLinked = 0
+  let noSubmitter = 0
+
+  for (const project of projects) {
+    if (!project.submittedByUserId) {
+      noSubmitter++
+      continue
+    }
+
+    const alreadyHasLink = project.teamMembers.some(
+      (tm) => tm.userId === project.submittedByUserId
+    )
+
+    if (alreadyHasLink) {
+      alreadyLinked++
+      continue
+    }
+
+    console.log(`  + Linking "${project.title}" → user ${project.submittedByUserId}`)
+
+    if (!dryRun) {
+      await prisma.teamMember.create({
+        data: {
+          projectId: project.id,
+          userId: project.submittedByUserId,
+          role: 'LEAD',
+        },
+      })
+    }
+
+    created++
+  }
+
+  console.log(`\n✅ Done!`)
+  console.log(`   ${created} TeamMember records ${dryRun ? 'would be' : ''} created`)
+  console.log(`   ${alreadyLinked} projects already had the submitter linked`)
+  console.log(`   ${noSubmitter} projects had no submitter`)
+  console.log(`   ${projects.length} total projects checked`)
+}
+
+main()
+  .catch((e) => {
+    console.error('❌ Error:', e)
+    process.exit(1)
+  })
+  .finally(() => prisma.$disconnect())