Add grid image system with multi-panel support and SPA routing

- Grid images: photograph component boxes in sub-sections, assemble
  into one logical grid via perspective warp (homography)
- Source image gallery: bulk upload photos separately from grid setup
- Grid drafts: persist partial work, resume across sessions
- Multi-panel grids: define rows/cols per photo, system computes panel
  layout; process partially configured grids, edit individual panels
- Pan/zoom canvas editor (HiDPI-aware, touch support) for corner alignment
- SPA routing with canonical URLs (history.pushState, server catch-all)
- Express error visibility: uncaughtException/unhandledRejection handlers
  and 4-arg error middleware
- Original filename stored on source image upload
- Various null-safety fixes and CSS [hidden] override fixes

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

package.json

@@ -2,11 +2,15 @@
 	"name": "electronics-inventory",
 	"version": "0.1.0",
 	"type": "module",
-	"engines": { "node": ">=25" },
+	"engines": {
+		"node": ">=25"
+	},
 	"scripts": {
 		"start": "node server.mjs"
 	},
 	"dependencies": {
-		"express": "^5.2.1"
+		"express": "^5.2.1",
+		"multer": "^2.1.1",
+		"sharp": "^0.34.5"
 	}
 }