feat(wallpaper-generator): add device wallpaper generation package

Add new @manacore/wallpaper-generator package for creating device
wallpapers from QR codes and images.

Features:
- 30 device presets (phones, tablets, desktops)
- 3 layout types (center, corner, pattern)
- 5 gradient presets + solid color backgrounds
- Browser (Canvas) and Node.js (Sharp) renderers
- Svelte WallpaperModal UI component

Integrations:
- @manacore/qr-export: toWallpaper() function
- @manacore/spiral-db: toWallpaper() function
- QRExportModal: "Als Wallpaper" button

Also includes the full @manacore/qr-export package which was
previously untracked.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

packages/wallpaper-generator/package.json

@@ -0,0 +1,38 @@
+{
+	"name": "@manacore/wallpaper-generator",
+	"version": "0.1.0",
+	"private": true,
+	"description": "Device wallpaper generator from QR codes and images",
+	"main": "./src/index.ts",
+	"types": "./src/index.ts",
+	"exports": {
+		".": "./src/index.ts",
+		"./svelte": "./src/svelte/index.ts",
+		"./presets": "./src/presets/index.ts"
+	},
+	"scripts": {
+		"type-check": "tsc --noEmit",
+		"clean": "rm -rf dist",
+		"lint": "eslint .",
+		"test": "vitest run",
+		"test:watch": "vitest"
+	},
+	"dependencies": {},
+	"devDependencies": {
+		"@types/node": "^24.10.1",
+		"typescript": "^5.9.3",
+		"vitest": "^3.0.5"
+	},
+	"peerDependencies": {
+		"svelte": "^5.0.0",
+		"sharp": "^0.33.0"
+	},
+	"peerDependenciesMeta": {
+		"svelte": {
+			"optional": true
+		},
+		"sharp": {
+			"optional": true
+		}
+	}
+}