feat(store): GOOD interop, rescan-merge, data staleness, lock detection

Task #5 building blocks, each a pure + unit-tested module:

- goodInterop.ts: GOOD (Genshin Optimizer / Inventory Kamera / Akasha) import and
  export for scanned StoredArtifactRecords - slot/stat/set key maps both ways,
  substat string <-> { key, value }, main-value reconstruction on import
  (ADR-003). Export is lossless; import is best-effort (GOOD lacks piece names).
- artifactMerge.ts: rescan-merge (ADR-006 follow-up). Level-independent identity
  (set + slot + main + substat NAME set) collapses leveled re-scan duplicates,
  keeping the higher-level/stronger record and summing timesSeen. Conservative:
  differing substat lineups never merge.
- dataPackageStatus.ts: warns when the genshin-db package is older than ~45 days
  (a patch cycle) so new sets/characters aren't silently missed; surfaced in the
  Scanner Diagnose data-package line. Adds dataGeneratedAt to genshinData.
- lockDetection.ts: EXPERIMENTAL read-only lock-status heuristic (gold-pixel
  ratio in a top-right icon crop). Pure + tested but not wired into capture; crop
  position and threshold need calibration against a reference 16:9 screenshot.

120 tests + build green. Remaining wiring (needs UI / live calibration): GOOD
import/export buttons and live lock detection.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/lib/lockDetection.ts

@@ -0,0 +1,52 @@
+import { clampRect, type LayoutRect } from "./layoutProfile";
+import type { Bitmap } from "./ocrPreprocess";
+
+// EXPERIMENTAL, read-only lock-status detection (nice-to-have). Genshin shows a
+// padlock at the top-right of the artifact detail card: a bright gold fill when
+// locked, a dim outline when not. This estimates that icon region and measures
+// the fraction of bright "lock-gold" pixels; above a threshold the piece is
+// considered locked.
+//
+// The crop position and threshold need calibration against a reference 16:9
+// screenshot before this is wired into the capture pipeline, so it ships pure and
+// unit-tested but unused by main.ts. It never drives any in-game action - it only
+// reads state for triage.
+
+export function lockIconCropRect(detailRect: LayoutRect, imageSize: { width: number; height: number }): LayoutRect {
+  return clampRect(
+    {
+      x: Math.round(detailRect.x + detailRect.width * 0.8),
+      y: Math.round(detailRect.y + detailRect.height * 0.03),
+      width: Math.round(detailRect.width * 0.16),
+      height: Math.round(detailRect.height * 0.09),
+    },
+    imageSize,
+  );
+}
+
+// A gold/highlighted lock pixel: red high, green mid-high, blue low.
+function isLockGold(b: number, g: number, r: number): boolean {
+  return r >= 180 && g >= 140 && b <= 120 && r > b + 40 && g > b + 20;
+}
+
+export function lockSignalRatio(bitmap: Bitmap): number {
+  const { data, width, height } = bitmap;
+  const pixels = width * height;
+  if (pixels === 0) return 0;
+  let gold = 0;
+  for (let pixel = 0; pixel < pixels; pixel++) {
+    const index = pixel * 4;
+    if (isLockGold(data[index], data[index + 1], data[index + 2])) gold++;
+  }
+  return gold / pixels;
+}
+
+export const DEFAULT_LOCK_THRESHOLD = 0.06;
+
+export function isLocked(signalRatio: number, threshold: number = DEFAULT_LOCK_THRESHOLD): boolean {
+  return signalRatio >= threshold;
+}
+
+export function detectLockState(bitmap: Bitmap, threshold: number = DEFAULT_LOCK_THRESHOLD): boolean {
+  return isLocked(lockSignalRatio(bitmap), threshold);
+}