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/.opencode/opencode.json

@@ -0,0 +1,18 @@
+{
+  "$schema": "https://opencode.ai/config.json",
+  "mcp": {
+    "nexusai": {
+      "type": "local",
+      "command": [
+        "node",
+        "/home/user/moder/mcp/NexusAI/packages/mcp-server/dist/index.js"
+      ],
+      "env": {
+        "NORDROUTER_API_KEY": "sk-your-key-here",
+        "NEXUS_MEDIA_DIR": "/home/user/moder/mcp/NexusAI/media-output",
+        "NEXUS_STT_MODEL": "small"
+      },
+      "enabled": true
+    }
+  }
+}