PM2 cluster deploy + Redis caching + Nginx gzip + UI polish

- PM2 v6: 2x API cluster + 1x web, zero-downtime reload
- Redis cache: 30s TTL on GET /tasks, X-Cache header
- Nginx gzip compression
- Mobile touch targets 44px
- Czech diacritics throughout UI
- TaskModal slide-up animation
- StatusBadge color dots
- GroupSelector emoji icons

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

api/package-lock.json

@@ -18,6 +18,7 @@
         "bcrypt": "^6.0.0",
         "dotenv": "^17.3.1",
         "fastify": "^5.8.4",
+        "ioredis": "^5.10.1",
         "pg": "^8.20.0",
         "redis": "^5.11.0",
         "uuid": "^13.0.0"
@@ -338,6 +339,12 @@
         "yaml": "^2.4.1"
       }
     },
+    "node_modules/@ioredis/commands": {
+      "version": "1.5.1",
+      "resolved": "https://registry.npmjs.org/@ioredis/commands/-/commands-1.5.1.tgz",
+      "integrity": "sha512-JH8ZL/ywcJyR9MmJ5BNqZllXNZQqQbnVZOqpPQqE1vHiFgAw4NHbvE0FOduNU8IX9babitBT46571OnPTT0Zcw==",
+      "license": "MIT"
+    },
     "node_modules/@lukeed/ms": {
       "version": "2.0.2",
       "resolved": "https://registry.npmjs.org/@lukeed/ms/-/ms-2.0.2.tgz",
@@ -660,6 +667,15 @@
         }
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     },
+    "node_modules/denque": {
+      "version": "2.1.0",
+      "resolved": "https://registry.npmjs.org/denque/-/denque-2.1.0.tgz",
+      "integrity": "sha512-HVQE3AAb/pxF8fQAoiqpvg9i3evqug3hoiwakOyZAwJm+6vZehbkYXZ0l4JxS+I3QxM97v5aaRNhj8v5oBhekw==",
+      "license": "Apache-2.0",
+      "engines": {
+        "node": ">=0.10"
+      }
+    },
     "node_modules/depd": {
       "version": "2.0.0",
       "resolved": "https://registry.npmjs.org/depd/-/depd-2.0.0.tgz",
@@ -995,6 +1011,30 @@
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       "license": "ISC"
     },
+    "node_modules/ioredis": {
+      "version": "5.10.1",
+      "resolved": "https://registry.npmjs.org/ioredis/-/ioredis-5.10.1.tgz",
+      "integrity": "sha512-HuEDBTI70aYdx1v6U97SbNx9F1+svQKBDo30o0b9fw055LMepzpOOd0Ccg9Q6tbqmBSJaMuY0fB7yw9/vjBYCA==",
+      "license": "MIT",
+      "dependencies": {
+        "@ioredis/commands": "1.5.1",
+        "cluster-key-slot": "^1.1.0",
+        "debug": "^4.3.4",
+        "denque": "^2.1.0",
+        "lodash.defaults": "^4.2.0",
+        "lodash.isarguments": "^3.1.0",
+        "redis-errors": "^1.2.0",
+        "redis-parser": "^3.0.0",
+        "standard-as-callback": "^2.1.0"
+      },
+      "engines": {
+        "node": ">=12.22.0"
+      },
+      "funding": {
+        "type": "opencollective",
+        "url": "https://opencollective.com/ioredis"
+      }
+    },
     "node_modules/ipaddr.js": {
       "version": "2.3.0",
       "resolved": "https://registry.npmjs.org/ipaddr.js/-/ipaddr.js-2.3.0.tgz",
@@ -1142,6 +1182,18 @@
       ],
       "license": "MIT"
     },
+    "node_modules/lodash.defaults": {
+      "version": "4.2.0",
+      "resolved": "https://registry.npmjs.org/lodash.defaults/-/lodash.defaults-4.2.0.tgz",
+      "integrity": "sha512-qjxPLHd3r5DnsdGacqOMU6pb/avJzdh9tFX2ymgoZE27BmjXrNy/y4LoaiTeAb+O3gL8AfpJGtqfX/ae2leYYQ==",
+      "license": "MIT"
+    },
+    "node_modules/lodash.isarguments": {
+      "version": "3.1.0",
+      "resolved": "https://registry.npmjs.org/lodash.isarguments/-/lodash.isarguments-3.1.0.tgz",
+      "integrity": "sha512-chi4NHZlZqZD18a0imDHnZPrDeBbTtVN7GXMwuGdRH9qotxAjYs3aVLKc7zNOG9eddR5Ksd8rvFEBc9SsggPpg==",
+      "license": "MIT"
+    },
     "node_modules/lru-cache": {
       "version": "11.2.7",
       "resolved": "https://registry.npmjs.org/lru-cache/-/lru-cache-11.2.7.tgz",
@@ -1550,6 +1602,27 @@
         "node": ">= 18"
       }
     },
+    "node_modules/redis-errors": {
+      "version": "1.2.0",
+      "resolved": "https://registry.npmjs.org/redis-errors/-/redis-errors-1.2.0.tgz",
+      "integrity": "sha512-1qny3OExCf0UvUV/5wpYKf2YwPcOqXzkwKKSmKHiE6ZMQs5heeE/c8eXK+PNllPvmjgAbfnsbpkGZWy8cBpn9w==",
+      "license": "MIT",
+      "engines": {
+        "node": ">=4"
+      }
+    },
+    "node_modules/redis-parser": {
+      "version": "3.0.0",
+      "resolved": "https://registry.npmjs.org/redis-parser/-/redis-parser-3.0.0.tgz",
+      "integrity": "sha512-DJnGAeenTdpMEH6uAJRK/uiyEIH9WVsUmoLwzudwGJUwZPp80PDBWPHXSAGNPwNvIXAbe7MSUB1zQFugFml66A==",
+      "license": "MIT",
+      "dependencies": {
+        "redis-errors": "^1.0.0"
+      },
+      "engines": {
+        "node": ">=4"
+      }
+    },
     "node_modules/require-from-string": {
       "version": "2.0.2",
       "resolved": "https://registry.npmjs.org/require-from-string/-/require-from-string-2.0.2.tgz",
@@ -1712,6 +1785,12 @@
         "node": ">= 10.x"
       }
     },
+    "node_modules/standard-as-callback": {
+      "version": "2.1.0",
+      "resolved": "https://registry.npmjs.org/standard-as-callback/-/standard-as-callback-2.1.0.tgz",
+      "integrity": "sha512-qoRRSyROncaz1z0mvYqIE4lCd9p2R90i6GxW3uZv5ucSu8tU7B5HXUP1gG8pVZsYNVaXjk8ClXHPttLyxAL48A==",
+      "license": "MIT"
+    },
     "node_modules/statuses": {
       "version": "2.0.2",
       "resolved": "https://registry.npmjs.org/statuses/-/statuses-2.0.2.tgz",