gate policy: frame-share is the verdict for owner-approved items; park after 2 failed rounds

Owner decision 2026-10-10. Eight items were livelocked in the nvenc tier, burning ~3.3
GPU-hours per pass (initial encode + quality+2 retry) and never converting: they missed the
mean bar by 0.2-1.7 thousandths (0.9626-0.9778) while keeping only 0.20-0.93% of frames
below 0.85 - and per this repo's own comment the FRAME-SHARE test is the one that actually
catches a defect, the mean bar splits a continuum. With SIZE_CEIL=1.0 the mean bar is
unreachable for them by construction.

- library_run.py: POLICY (C:\AI\transcode-run\gate_policy.json) with
  * accept - named items are judged by the frame-share test; a mean under the bar is logged,
    not enforced. An item that trips the frame-share test is refused even if listed
    (0912 洞见, 1.33%, is deliberately absent).
  * park  - failed quality ROUNDS per item; at PARK_AFTER=2 the item is skipped with a
    visible SKIP status instead of being re-encoded. Counters persist in the same file.
- scripts/build_gate_policy.py: builds that file from the run log, taking each key verbatim
  from the '--- i/n <relative path>' line (no hand-copying). Result: 7 accepted, 1 refused.
- run/relaunch_nvenc.sh: start the GPU tier ALONE (relaunch_tiers.sh hardcodes both tiers).
- STATE.md: the policy, its rationale and the round counter.

scripts/build_gate_policy.py

@@ -0,0 +1,63 @@
+#!/usr/bin/env python3
+"""Build C:\\AI\\transcode-run\\gate_policy.json from today's nvenc run log.
+
+Owner decision 2026-10-10: items that failed the quality gate today are split by the FRAME-SHARE
+test (>1% of frames below 0.85 = the documented real defect test, and the only one of the eight that
+trips it is 0912 洞见 at 1.33%). Items passing the frame-share test go on the accept list, so the
+mean bar stops stranding them; every item that failed a round today gets park=1, so one more failure
+parks it (PARK_AFTER=2) instead of re-encoding it forever.
+
+Keys are taken verbatim from the log's "--- i/n <disp key>" lines, never retyped.
+"""
+import json, os, re, subprocess, sys
+
+LOG = r"D:\tmp\xcode\run_nvenc.log"
+POLICY = r"C:\AI\transcode-run\gate_policy.json"
+MARK = "nvenc relaunch attempt 1"      # only today's run
+
+items = []          # (disp key, bad share %, mean, bar)
+last = None
+seen = False
+for line in open(LOG, encoding="utf-8", errors="replace"):
+    if MARK in line:
+        seen = True
+    if not seen:
+        continue
+    m = re.match(r"^\d\d:\d\d:\d\d --- \d+/\d+ (.+?)\s*$", line)
+    if m:
+        last = m.group(1)
+        continue
+    if "!! FAIL quality" in line and last:
+        sh = re.search(r"([\d.]+)% of frames below", line)
+        mn = re.search(r"mean ([\d.]+) < bar ([\d.]+)", line)
+        items.append((last, float(sh.group(1)) if sh else None,
+                      float(mn.group(1)) if mn else None, float(mn.group(2)) if mn else None))
+        last = None
+
+# de-duplicate (an item may fail more than once in a log), keep the worst share
+worst = {}
+for k, sh, mn, bar in items:
+    if k not in worst or (sh or 0) > (worst[k] or 0):
+        worst[k] = sh
+
+accept, park, refused = [], {}, []
+for k, sh in worst.items():
+    park[k] = 1                     # one failed round today; the next failure parks it
+    if sh is not None and sh > 1.0:
+        refused.append((k, sh))
+    else:
+        accept.append(k)
+
+os.makedirs(os.path.dirname(POLICY), exist_ok=True)
+with open(POLICY, "w", encoding="utf-8") as fh:
+    json.dump({"accept": sorted(accept), "park": park}, fh, ensure_ascii=False, indent=1)
+
+print("failed items today:", len(worst))
+print("ACCEPT (frame-share <= 1%%): %d" % len(accept))
+for k in sorted(accept):
+    print("   ", k, "  (worst share %.2f%%)" % worst[k])
+print("REFUSED (frame-share > 1%%, keeps failing): %d" % len(refused))
+for k, sh in refused:
+    print("   ", k, "  (%.2f%%)" % sh)
+print("park seeded at 1 round for all of them -> parked at PARK_AFTER=2")
+print("wrote", POLICY)