Add application migration workflow.

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/migrations/014_application_migrations.sql

@@ -0,0 +1,36 @@
+CREATE TABLE IF NOT EXISTS application_migration_jobs (
+  id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+  "applicationId" UUID NOT NULL REFERENCES applications(id) ON DELETE CASCADE,
+  "requestedBy" UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+  "sourceClusterId" UUID NOT NULL REFERENCES clusters(id) ON DELETE RESTRICT,
+  "targetClusterId" UUID NOT NULL REFERENCES clusters(id) ON DELETE RESTRICT,
+  status VARCHAR NOT NULL DEFAULT 'queued',
+  attempts INTEGER NOT NULL DEFAULT 0,
+  "maxAttempts" INTEGER NOT NULL DEFAULT 3,
+  "currentStep" VARCHAR,
+  "errorMessage" VARCHAR,
+  metadata JSONB,
+  "startedAt" TIMESTAMPTZ,
+  "completedAt" TIMESTAMPTZ,
+  "createdAt" TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+  "updatedAt" TIMESTAMPTZ NOT NULL DEFAULT NOW()
+);
+
+CREATE INDEX IF NOT EXISTS idx_application_migration_jobs_app_created
+  ON application_migration_jobs("applicationId", "createdAt" DESC);
+
+CREATE INDEX IF NOT EXISTS idx_application_migration_jobs_status
+  ON application_migration_jobs(status);
+
+CREATE TABLE IF NOT EXISTS application_migration_events (
+  id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+  "migrationId" UUID NOT NULL REFERENCES application_migration_jobs(id) ON DELETE CASCADE,
+  step VARCHAR NOT NULL,
+  level VARCHAR NOT NULL DEFAULT 'info',
+  message VARCHAR NOT NULL,
+  metadata JSONB,
+  "createdAt" TIMESTAMPTZ NOT NULL DEFAULT NOW()
+);
+
+CREATE INDEX IF NOT EXISTS idx_application_migration_events_migration_created
+  ON application_migration_events("migrationId", "createdAt" ASC);