Improve scanner repeatability guardrails

docs/AUTOMATION_LIVE_SCAN.md

@@ -268,10 +268,20 @@ Latest live timing evidence on 2026-07-08:
   signature `2026-07-08-direct-gdi-reviewfix` completed `20/20`, `18` stored,
   `0` review, `2` duplicates, `0` misses, `7973 ms` elapsed, or
   `399 ms/artifact`. 3 artifacts/second is not proven.
+- Follow-up 3 artifacts/second attempts on 2026-07-09:
+  after the distinctive partial piece parser fix, the best clean repeatability
+  run reached `336 ms/artifact` with `20/20` parsed, `0` review, `0` misses,
+  `318 ms` average capture roundtrip, and `138 ms` roundtrip overhead. Later
+  runs with crop priority and image-payload cleanup stayed clean but ranged
+  around `346-351 ms/artifact`; the strict `333 ms/artifact` budget remains
+  unproven.
 - Rejected speed experiments:
   detail-region capture, `GAA_OCR_WORKERS=5`, DataURL-to-buffer decode, and
   substat OCR `PSM.SINGLE_COLUMN` were all live/benchmark tested and were slower
-  than the direct-GDI baseline. Keep `GAA_OCR_WORKERS=4` for current runs.
+  than the direct-GDI baseline. Later checks also rejected skipping
+  `analyzePaimonMenu`, skipping lock-state as a production shortcut, reducing
+  the artifact-level crop scale, and `GAA_OCR_WORKERS=6` as the default.
+  Keep `GAA_OCR_WORKERS=4` for current runs.
 - Quality-gated current-vs-IK comparison:
   `npm run scan:goal:compare:validated` produced
   `outputs/live-soak/2026-07-08T18-38-35/scan-performance-assessment.json`
@@ -449,15 +459,17 @@ uses the default `current` scan engine; use `scan:goal:ik` for a native
 IK-traineddata scan pass. Use `scan:goal:compare` to run both scan engines
 back-to-back with the same limits and one combined CSV. The CSV is the quickest evidence for
 `averageMsPerParsed`, `activeAverageMsPerParsed`, `averageCaptureMs`,
+`averageCaptureRoundTripMs`, `averageCaptureRoundTripOverheadMs`,
 `captureP50Ms`, `captureP90Ms`, `averageOcrMs`, `ocrP50Ms`, `ocrP90Ms`,
 `averageCardReadyMs`, `averageScrollReadyMs`, `artifactsPerMinute`, and
 `projectedMsFor100`.
 The run also writes `scan-performance-assessment.json`, which groups results by
 limit, picks the best qualified engine, and labels the dominant bottleneck as
-OCR, capture, card-ready, or scroll-ready. A qualified winner must finish the
-run, parse the requested count, keep miss rate under 2%, and keep review rate
-at or below 15%; review and miss rates are penalized before active average speed
-is used as the tie-breaker. For IK-target claims, check `goal100Decision`; it
+OCR, capture-roundtrip-overhead, capture, card-ready, or scroll-ready. A
+qualified winner must finish the run, parse the requested count, keep miss rate
+under 2%, and keep review rate at or below 15%; review and miss rates are
+penalized before active average speed is used as the tie-breaker. For IK-target
+claims, check `goal100Decision`; it
 must read `qualified-comparison: winner=<engine>`, and
 `goal100.comparisonComplete` must be `true` so a single-engine 100-artifact run
 is not mistaken for a current-vs-IK comparison.
@@ -478,12 +490,38 @@ instead of the final 100-artifact proof. Add `--summary` when you want a short
 report-ready PASS/FAIL output that includes the input assessment path and
 assessment `createdAt` timestamp.
 
+Optional budget flags are useful for the current speed work:
+
+```powershell
+npm run scan:assessment:validate -- --latest --summary --limit=20 --max-active-average-ms=333 --max-capture-roundtrip-overhead-ms=120
+```
+
+`--max-active-average-ms=333` is the strict 3 artifacts/second check. Use a
+separate `--max-capture-roundtrip-overhead-ms` budget when deciding whether the
+next optimization belongs in native capture transport instead of OCR.
+Single-engine repeatability runs may be validated with `--allow-single-engine`,
+but that mode is only for repeatability evidence and must not be used for IK
+parity claims.
+
 `npm run scan:goal:compare:validated` is the preferred final command: it runs
 the live preflight first, then the full comparison, and then validates the
 newest assessment with `--summary`. Use
 `npm run scan:goal:compare:validated:wait` for the same final flow when starting
 immediately after UAC.
 
+For later-session repeatability without changing OCR engines, use:
+
+```powershell
+npm run scan:repeatability:wait
+```
+
+That command runs the current visible-inventory engine at 20, 45, and 100
+artifacts, then validates the 100-artifact result as single-engine evidence.
+It uses the `live-soak.ps1 -RepeatabilityRun` switch instead of passing a
+comma-separated `-Limits` value through npm/cmd, because Windows argument
+parsing can collapse `20,45,100` into one unsafe number. The script also refuses
+limits above 1800 as a final guard.
+
 The assessment ranking can be verified without Genshin or the Electron app:
 
 ```powershell