feat(TASK-032): review-gauntlet incomplete-review machine line + ×N attempt details

verdict_gate.py now names every incomplete review on a machine line the
done template renders immediately after the verdict:
`GAUNTLET_REVIEW_INCOMPLETE: <name>[, <name>]` (sorted). Names are the
lanes retry_gate gave up on (`review_incomplete`) plus the `pipeline`
pseudo-lane whenever `signals_error` carries a `PIPELINE-FAULT:` —
parse death, builder / retry-gate / default-lanes crash guards — and the
gate's own crash guard emits the `pipeline` line too. The report gains a
`## Review incomplete` section (after the signals_error blockquote,
immediately before `## Full lane reports`) and the three PIPELINE-FAULT
lane rows carry ` ×N` when the lane was re-run (N = 1 texts unchanged).

retry_gate.py stands in a synthetic `PIPELINE-FAULT: <lane> lane produced
no report` marker for a lane that ran but collected nothing, so it is
stashed, classified FAULTED and never renders SKIPPED downstream.
MAX_RETRY_ELAPSED_SECS trimmed 45600 → 45000 for margin slack.

graph.yaml: `gauntlet_incomplete_line` seeded in initial_state and
spliced into the done output. README + mermaid document retry_gate, the
dotted _next back-edge, the 3-attempt / wall-clock budget, that retry
never narrows selection, the crash-guard append semantics, and the
machine-line contract (present whenever any lane or the pipeline was
incomplete; it can accompany real findings).

Tests: ×N on all three branches (N>1, N=1 byte-identical, no leak onto
non-fault rows), exact incomplete line / section placement, pipeline
pseudo-lane alone and alongside real lanes (via default_lanes.py's real
crash guard), mixed finding+fault, crash-guard chaining from
build_items / retry_gate / parse_fault / verdict_gate, synthetic
no-report marker, done-template wiring, README pins (positive + stale
negative).

assets/agents/review-gauntlet/scripts/retry_gate.py

@@ -10,7 +10,9 @@ hard rules:
     and faulted alike, and a lane whose map ran nothing this pass gets
     its stashed report restored — the verdict gate always sees each
     lane's LAST report;
-  - a lane is FAULTED only when its report is missing, non-string, the
+  - a lane is FAULTED only when its report is missing (the map ran but
+    collected nothing — replaced by a synthetic PIPELINE-FAULT marker so
+    the verdict gate never reads it as SKIPPED), non-string, the
     lane_fault.py marker, sentinel-less, or carries the nested graph's own
     degraded-run wording; a real verdict (DIVERGES, FAIL, INCONCLUSIVE,
     NEEDS-HUMAN, …) is never re-run — the review's judgment stands;
@@ -27,7 +29,9 @@ import os
 import re
 import time
 
-MAX_RETRY_ELAPSED_SECS = 45600
+# 69600 (graph timeout) − 2 × 11400 (largest lane envelope) − 1200 (script stages)
+# = 45600; 600 s of slack below that.
+MAX_RETRY_ELAPSED_SECS = 45000
 MAX_ATTEMPTS = 3
 
 # lane name -> (items key, results key)
@@ -114,8 +118,10 @@ def main():
                 out[results_key] = [kept[lane]]
             continue
         report = results[0] if results else None
-        if report is not None:
-            kept[lane] = report
+        if report is None:
+            report = f"PIPELINE-FAULT: {lane} lane produced no report"
+            out[results_key] = [report]
+        kept[lane] = report
         if is_faulted(lane, report):
             faulted.append(lane)
         attempts[lane] = int(attempts.get(lane) or 0) + 1