feat(ocr): resolution-anchored layout module + crop preprocessing

Implements ADR-009 (structure + preprocessing; exact IK fixed coordinates still
need calibration against a reference 16:9 screenshot).

- src/lib/layoutProfile.ts: pure, unit-tested geometry for the artifact screen -
  detail rect, the four detail crops, inventory rect/count crop, 5-col grid,
  16:9 detection, aspect label, and an off-16:9 support warning. Single source of
  truth; electron/main.ts now delegates all crop/grid geometry to it and keeps
  colour detection only as the detail-rect fallback.
- src/lib/ocrPreprocess.ts: pure, unit-tested Otsu binarization with inversion
  (artifact text is the bright foreground) over a BGRA bitmap.
- main.ts: OCR now reads an upscaled + binarized copy of each crop; the original
  crop is retained for the diagnostics UI. CaptureResult carries layout info
  { aspect, isSixteenNine, warning }.

NOTE: image preprocessing changes the OCR input and cannot be validated by the
text-level eval harness; it needs a live Genshin 16:9 capture to confirm/tune
(threshold, invert, upscale factor). 88 tests + build green.

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

src/types/global.d.ts

@@ -56,6 +56,11 @@ export interface CaptureResult {
     source: "ocr" | "missing";
     text: string;
   };
+  layout?: {
+    aspect: string;
+    isSixteenNine: boolean;
+    warning: string;
+  };
 }
 
 export interface WindowBounds {