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/tsconfig.json

@@ -0,0 +1,18 @@
+{
+  "compilerOptions": {
+    "target": "ES2022",
+    "module": "CommonJS",
+    "moduleResolution": "node",
+    "declaration": true,
+    "declarationMap": true,
+    "sourceMap": true,
+    "outDir": "dist",
+    "rootDir": "src",
+    "strict": true,
+    "esModuleInterop": true,
+    "skipLibCheck": true,
+    "forceConsistentCasingInFileNames": true,
+    "resolveJsonModule": true
+  },
+  "include": ["src/**/*"]
+}