feat: receipt PDF save and print via html2pdf.js

- Save PDF button downloads receipt directly
- Print button opens PDF in new window and triggers print dialog
- Replaces previous window.print() approach that lost styles
- Receipt generated on demand from transaction data, no file storage needed

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

bun.lock

@@ -34,6 +34,7 @@
         "class-variance-authority": "^0.7.1",
         "clsx": "^2.1.1",
         "date-fns": "^4.1.0",
+        "html2pdf.js": "^0.14.0",
         "jsbarcode": "^3.12.3",
         "jspdf": "^4.2.1",
         "lucide-react": "^1.7.0",
@@ -807,6 +808,8 @@
 
     "html2canvas": ["html2canvas@1.4.1", "", { "dependencies": { "css-line-break": "^2.1.0", "text-segmentation": "^1.0.3" } }, "sha512-fPU6BHNpsyIhr8yyMpTLLxAbkaK8ArIBcmZIRiBLiDhjeqvXolaEmDGmELFuX9I4xDcaKKcJl+TKZLqruBbmWA=="],
 
+    "html2pdf.js": ["html2pdf.js@0.14.0", "", { "dependencies": { "dompurify": "^3.3.1", "html2canvas": "^1.0.0", "jspdf": "^4.0.0" } }, "sha512-yvNJgE/8yru2UeGflkPdjW8YEY+nDH5X7/2WG4uiuSCwYiCp8PZ8EKNiTAa6HxJ1NjC51fZSIEq6xld5CADKBQ=="],
+
     "ignore": ["ignore@5.3.2", "", {}, "sha512-hsBTNUqQTDwkWtcdYI2i06Y/nUBEsNEDJKjWdigLvegy8kDuJAS8uRlpkkcQpyEXL0Z/pjDy5HBmMjRCJ2gq+g=="],
 
     "import-fresh": ["import-fresh@3.3.1", "", { "dependencies": { "parent-module": "^1.0.0", "resolve-from": "^4.0.0" } }, "sha512-TR3KfrTZTYLPB6jUjfx6MF9WcWrHL9su5TObK4ZkYgBdWKPOFoSoQIdEuTuR82pmtxH2spWG9h6etwfr1pLBqQ=="],