fix: resolve botched stash-pop conflict from 245e1280e

- scripts/lib/test-quarantine.json: remove stray <<<<<<< / ======= / >>>>>>> stash markers that broke JSON parsing
- packages/core/src/__test-utils__/vitest-setup.ts: restore \r?\n regex and \n template escapes; drop stray extra brace

packages/core/src/__test-utils__/vitest-setup.ts

@@ -211,8 +211,7 @@ function sweepDeadTmpdirRedirectSinks(): void {
   try {
     ownerPids = Array.from(new Set(
       readFileSync(TMPDIR_REDIRECT_REGISTRY, "utf8")
-        .split(/
-?
+        .split(/\r?\n/)
         .map((line) => Number.parseInt(line, 10))
         .filter((pid) => Number.isInteger(pid) && pid > 0),
     ));
@@ -249,9 +248,7 @@ function sweepDeadTmpdirRedirectSinks(): void {
   }
 
   try {
-  try {
-    writeFileSync(TMPDIR_REDIRECT_REGISTRY, liveOwnerPids.length > 0 ? `${liveOwnerPids.join("
-")}
+    writeFileSync(TMPDIR_REDIRECT_REGISTRY, liveOwnerPids.length > 0 ? `${liveOwnerPids.join("\n")}\n` : "");
   } catch {
     // Best-effort only; stale entries are harmless and swept by future workers.
   }
@@ -264,8 +261,7 @@ function ensureTmpdirRedirectSink(): string {
   const sink = join(WORKER_ROOT, `redir-${process.pid}`);
   mkdirSync(sink, { recursive: true });
   try {
-  try {
-    appendFileSync(TMPDIR_REDIRECT_REGISTRY, `${process.pid}
+    appendFileSync(TMPDIR_REDIRECT_REGISTRY, `${process.pid}\n`);
   } catch {
     // Best-effort only; the process exit hook and global teardown still clean up.
   }
@@ -298,7 +294,6 @@ function redirectTmpdirPrefix<T>(prefix: T): T {
 
   return join(ensureTmpdirRedirectSink(), basename(prefix)) as T;
 }
-}
 
 function ensureIsolatedHome(): void {
   const existingHome = process.env.HOME ?? process.env.USERPROFILE;

scripts/lib/test-quarantine.json

@@ -11,10 +11,6 @@
       "reason": "Flake: vi.mock('node:child_process') occasionally doesn't take under workspace-concurrent runs, letting real git binary leak and report staged files unrelated to test scope (trips FileScopeViolationError). Same logic covered by real-git fixture tests in reliability-interactions/workflow-and-file-scope. FN-6206.",
       "quarantinedAt": "2026-06-10"
     },
-<<<<<<< Updated upstream
-=======
-
->>>>>>> Stashed changes
     {
       "file": "packages/engine/src/__tests__/merger-ai-cleanup.test.ts",
       "reason": "Flake observed during FN-6206 verification: `pruneExistingAiMergeWorktrees skips active-session paths` failed in full `pnpm --filter @fusion/engine test` runs while the file passed standalone, indicating suite-order/concurrency sensitivity. Follow-up FN-6207.",