Donate stranka: PAY by square QR s vyberom sumy

Linka Na kavu v hlavicke lobby vedie na /donate. QR sa generuje
dynamicky (balicek bysquare) pre presety 1/2/5 EUR alebo vlastnu sumu;
IBAN sa da skopirovat do schranky. Navstevy loguje existujuci
pageview beacon.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

frontend/package-lock.json

@@ -8,6 +8,7 @@
       "name": "bridzik-frontend",
       "version": "0.1.0",
       "dependencies": {
+        "bysquare": "^4.0.0",
         "qrcode.react": "^4.1.0",
         "react": "^18.3.1",
         "react-dom": "^18.3.1",
@@ -3152,6 +3153,22 @@
       "dev": true,
       "license": "MIT"
     },
+    "node_modules/bysquare": {
+      "version": "4.0.0",
+      "resolved": "https://registry.npmjs.org/bysquare/-/bysquare-4.0.0.tgz",
+      "integrity": "sha512-V1gGJFn39TY9XnvQDbzMTgGau3wCatsH5+XNSC2wXGgYijIVUD0gkZGalNIub28R+XhM/zUvge+8ccMPJ2+bZw==",
+      "license": "Apache-2.0",
+      "dependencies": {
+        "lzma1": "0.2.0",
+        "validator": "^13.15.26"
+      },
+      "bin": {
+        "bysquare": "lib/cli.js"
+      },
+      "funding": {
+        "url": "https://github.com/sponsors/xseman"
+      }
+    },
     "node_modules/call-bind": {
       "version": "1.0.9",
       "resolved": "https://registry.npmjs.org/call-bind/-/call-bind-1.0.9.tgz",
@@ -5096,6 +5113,15 @@
         "yallist": "^3.0.2"
       }
     },
+    "node_modules/lzma1": {
+      "version": "0.2.0",
+      "resolved": "https://registry.npmjs.org/lzma1/-/lzma1-0.2.0.tgz",
+      "integrity": "sha512-JkPtHHKANh2je4Gp2kTjtobUXf7+zzfGHYm9PPRnx+Mr4KhAqoyb8dwtCExGaxkJl5upwWStdkIJWpn28XWiHw==",
+      "license": "MIT",
+      "funding": {
+        "url": "https://github.com/sponsors/xseman"
+      }
+    },
     "node_modules/magic-string": {
       "version": "0.30.21",
       "resolved": "https://registry.npmjs.org/magic-string/-/magic-string-0.30.21.tgz",
@@ -6952,6 +6978,15 @@
       "dev": true,
       "license": "MIT"
     },
+    "node_modules/validator": {
+      "version": "13.15.35",
+      "resolved": "https://registry.npmjs.org/validator/-/validator-13.15.35.tgz",
+      "integrity": "sha512-TQ5pAGhd5whStmqWvYF4OjQROlmv9SMFVt37qoCBdqRffuuklWYQlCNnEs2ZaIBD1kZRNnikiZOS1eqgkar0iw==",
+      "license": "MIT",
+      "engines": {
+        "node": ">= 0.10"
+      }
+    },
     "node_modules/victory-vendor": {
       "version": "36.9.2",
       "resolved": "https://registry.npmjs.org/victory-vendor/-/victory-vendor-36.9.2.tgz",