feat(webui): add SkillHub marketplace source

webui/src/i18n/locales/en/common.json

@@ -791,6 +791,29 @@
       "views": "Skills views",
       "installedTab": "Installed",
       "discoverTab": "Discover",
+      "marketplaceSearchFailed": "Could not search skill marketplaces.",
+      "marketplaceInstallFailed": "Could not install this skill.",
+      "marketplaceSearchPlaceholder": "Search skills",
+      "marketplaceSearchLabel": "Search skills",
+      "marketplaceSearching": "Searching",
+      "marketplaceProviderFilter": "Skill source",
+      "marketplaceProviderAll": "All",
+      "marketplaceTrendingTitle": "Trending by marketplace",
+      "marketplaceTrendingDescription": "Each marketplace keeps its own ranking and install metrics.",
+      "marketplaceViewAll": "View all",
+      "marketplaceTrendingUnavailable": "Trending skills are temporarily unavailable.",
+      "marketplaceEmpty": "No skills found for “{{query}}”.",
+      "marketplaceConfirmTitle": "Install {{name}}?",
+      "marketplaceConfirmDescription": "This third-party skill comes from {{provider}} ({{source}}) and may include instructions or executable scripts.",
+      "marketplaceConfirmInstall": "Install skill",
+      "marketplaceOpen": "Open {{name}} on {{provider}}",
+      "marketplaceInstalls24h": "{{formattedCount}} installs / 24h",
+      "marketplaceInstalls": "{{formattedCount}} installs",
+      "marketplaceNpxRequired": "Node.js with npx is required",
+      "marketplaceInstalling": "Installing",
+      "marketplaceInstalled": "Installed",
+      "marketplaceInstall": "Install",
+      "marketplaceNoTrend": "No trend yet",
       "featured": "Agent skills",
       "empty": "No skills are available.",
       "sourceWorkspace": "Custom",