exp+fix: commit2 增益重扫（gain2.2 到达 50.8%，n=512）+ 浏览器安全层三点修复（限位夹紧/部分前缀/离散认证）

- gain 1.8/2.2/2.5/2.8 = 50.4/52.0/49.6/47.7%（n=256），2.2 最佳；n=512 复核 50.8%/1.4% 碰撞
- 积分反馈与反馈隔次复用均为负结论（−4.0/−5.1 pp）
- JS：tick/候选投影夹 LIM（原越限后 inBox 永久拒绝→刹停）；safety_partial 移植；segCert 开关（默认严格）
- bench nc10 --seg 0：刹车率 79.5→48.1%、planP50 56.1→33.5ms、ok 0→5/10

ml/eval/eval_cl.py

@@ -42,6 +42,7 @@ def main():
     ap.add_argument('--ki', type=float, default=0.0)
     ap.add_argument('--kdecay', type=float, default=0.9)
     ap.add_argument('--kimax', type=float, default=0.5)
+    ap.add_argument('--fb_every', type=int, default=1)
     ap.add_argument('--select', default='consist')
     ap.add_argument('--replan', default='r3')
     ap.add_argument('--safety', type=int, default=1, help='1=安全层+部分前缀；0=关')
@@ -62,7 +63,8 @@ def main():
     t0 = time.perf_counter()
     r = run(model, kin, tasks, a.device, K=a.K, safety=bool(a.safety), seed=a.seed, max_sec=a.max_sec,
             safety_partial=(a.commit if (a.safety and a.partial) else 0), commit_n=a.commit,
-            select=a.select, replan=a.replan, fb_gain=a.fb, fb_ki=a.ki, fb_decay=a.kdecay, fb_imax=a.kimax)
+            select=a.select, replan=a.replan, fb_gain=a.fb, fb_ki=a.ki, fb_decay=a.kdecay, fb_imax=a.kimax,
+            fb_every=a.fb_every)
     wall = time.perf_counter() - t0
     print('ckpt=%s n=%d K=%d commit=%d fb=%.2f ki=%.2f select=%s replan=%s safety=%d' %
           (a.ckpt, r['n'], a.K, a.commit, a.fb, a.ki, a.select, a.replan, a.safety))