feat: prisma schema User + SyncRun + seed admin

Sets up Prisma 7 with SQLite (better-sqlite3 adapter), User and SyncRun models, migration, and admin seed account for mathieu.fort@gmail.com.

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

src/lib/prisma.ts

@@ -0,0 +1,23 @@
+import { PrismaClient } from '@prisma/client'
+import { PrismaBetterSqlite3 } from '@prisma/adapter-better-sqlite3'
+import path from 'path'
+
+function createPrismaClient() {
+  const dbUrl = process.env.DATABASE_URL ?? 'file:./data/dev.db'
+  // Parse the file path from "file:./data/dev.db" format
+  const dbPath = dbUrl.startsWith('file:')
+    ? path.resolve(process.cwd(), dbUrl.slice('file:'.length))
+    : dbUrl
+
+  const adapter = new PrismaBetterSqlite3({ url: dbPath })
+  return new PrismaClient({
+    adapter,
+    log: process.env.NODE_ENV === 'development' ? ['error'] : [],
+  })
+}
+
+const globalForPrisma = globalThis as unknown as { prisma: PrismaClient }
+
+export const prisma = globalForPrisma.prisma ?? createPrismaClient()
+
+if (process.env.NODE_ENV !== 'production') globalForPrisma.prisma = prisma