feat(db): add Job.paused column for per-item press pause

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

web/prisma/migrations/20260715000000_add_job_paused/migration.sql

@@ -0,0 +1,2 @@
+-- AlterTable
+ALTER TABLE "Job" ADD COLUMN     "paused" BOOLEAN NOT NULL DEFAULT false;

web/prisma/schema.prisma

@@ -58,6 +58,7 @@ model Job {
   createdAt        DateTime    @default(now())
   updatedAt        DateTime    @updatedAt
   downloadProgress Float       @default(0)
+  paused           Boolean     @default(false)
   candidates       Candidate[]
 }