chore: ruff auto-fix C401, C416, C408, PLR1722 (#23940)

C401:   set(x for x in y) -> {x for x in y}      (set comprehension)
C416:   [(k,v) for k,v in d] -> list(d.items())  (unnecessary listcomp)
C408:   tuple()/dict() -> ()/{}                   (unnecessary collection call)
PLR1722: exit() -> sys.exit()                     (adds import sys where needed)

21 instances fixed, 0 remaining. 19 files, +40/-36.

scripts/profile-tui.py

@@ -343,7 +343,7 @@ def key_metrics(data: dict[str, Any]) -> dict[str, float]:
         metrics["backpressure_frames"] = bp
 
     if react:
-        for pid in set(e["id"] for e in react):
+        for pid in {e["id"] for e in react}:
             ms = [e["actualMs"] for e in react if e["id"] == pid]
             metrics[f"react_{pid}_p99"] = pct(ms, 0.99)
             metrics[f"react_{pid}_max"] = max(ms)

scripts/release.py

@@ -1426,7 +1426,7 @@ def main():
     print(f"  SemVer:          v{current_version} → v{new_version}")
     print(f"  Previous tag:    {prev_tag or '(none — first release)'}")
     print(f"  Commits:         {len(commits)}")
-    print(f"  Unique authors:  {len(set(c['github_author'] for c in commits))}")
+    print(f"  Unique authors:  {len({c['github_author'] for c in commits})}")
     print(f"  Mode:            {'PUBLISH' if args.publish else 'DRY RUN'}")
     print(f"{'='*60}")
     print()