Add NexusAI: universal MCP service (TTS/STT/image/video/music/web-search)

Monorepo-lite with shared @nexusai/core and @nexusai/mcp-server (stdio).
Provider-agnostic tools with explicit provider selection; NordRouter adapter
(media generate/poll/download, estimate, upload, models) and search via
perplexity/sonar. Local STT via faster-whisper uv sidecar. SQLite journal of
every generation for usage stats and future admin. 10 MCP tools.

NexusAI/packages/core/package.json

@@ -0,0 +1,22 @@
+{
+  "name": "@nexusai/core",
+  "version": "0.1.0",
+  "description": "NexusAI shared core: providers, media storage, journal, types",
+  "main": "dist/index.js",
+  "types": "dist/index.d.ts",
+  "type": "commonjs",
+  "scripts": {
+    "build": "tsc",
+    "dev": "tsc --watch"
+  },
+  "dependencies": {
+    "better-sqlite3": "^11.8.0",
+    "undici": "^6.27.0",
+    "zod": "^3.25.0"
+  },
+  "devDependencies": {
+    "@types/better-sqlite3": "^7.6.0",
+    "@types/node": "^22.15.0",
+    "typescript": "^5.8.0"
+  }
+}