ci: merge biome configs to fix nested config error

Root and services/frontend each had a biome.json causing Biome to
error on nested configuration. Merged frontend-specific rules and
domains (next, react) into root biome.json, removed nested config.

services/frontend/biome.json

@@ -1,53 +0,0 @@
-{
-  "$schema": "https://biomejs.dev/schemas/2.2.0/schema.json",
-  "vcs": {
-    "enabled": true,
-    "clientKind": "git",
-    "useIgnoreFile": true
-  },
-  "files": {
-    "ignoreUnknown": true,
-    "includes": ["**", "!node_modules", "!.next", "!dist", "!build"]
-  },
-  "formatter": {
-    "enabled": true,
-    "indentStyle": "space",
-    "indentWidth": 2
-  },
-  "linter": {
-    "enabled": true,
-    "rules": {
-      "recommended": true,
-      "suspicious": {
-        "noUnknownAtRules": "off",
-        "useIterableCallbackReturn": "off",
-        "noArrayIndexKey": "warn"
-      },
-      "a11y": {
-        "useButtonType": "off",
-        "noAutofocus": "off"
-      },
-      "performance": {
-        "noImgElement": "warn"
-      },
-      "security": {
-        "noDangerouslySetInnerHtml": "warn"
-      },
-      "correctness": {
-        "noInvalidUseBeforeDeclaration": "off",
-        "noUnusedFunctionParameters": "warn"
-      }
-    },
-    "domains": {
-      "next": "recommended",
-      "react": "recommended"
-    }
-  },
-  "assist": {
-    "actions": {
-      "source": {
-        "organizeImports": "on"
-      }
-    }
-  }
-}

services/frontend/components.json

@@ -1,25 +0,0 @@
-{
-  "$schema": "https://ui.shadcn.com/schema.json",
-  "style": "base-nova",
-  "rsc": true,
-  "tsx": true,
-  "tailwind": {
-    "config": "",
-    "css": "src/app/globals.css",
-    "baseColor": "neutral",
-    "cssVariables": true,
-    "prefix": ""
-  },
-  "iconLibrary": "lucide",
-  "rtl": false,
-  "aliases": {
-    "components": "@/components",
-    "utils": "@/lib/utils",
-    "ui": "@/components/ui",
-    "lib": "@/lib",
-    "hooks": "@/hooks"
-  },
-  "menuColor": "default",
-  "menuAccent": "subtle",
-  "registries": {}
-}