fix(cli): route node-target serve through @flue/runtime/node

[k161196]

Node-target builds returned HTTP 500 on every WebSocket upgrade to /agents/:name/:id. Cause: dual-instance Symbol mismatch.

• @flue/cli bundled @hono/node-server into generated dist/server.mjs; the bundled copy attached WAIT_FOR_WEBSOCKET_SYMBOL on env.
• Generated entry also imported createNodeWebSocketTransport from @flue/runtime/node (external), which re-imported upgradeWebSocket from the disk copy of @hono/node-server.
• Two module instances => two distinct Symbol identities. injectWebSocket wrote symbol A; upgradeWebSocket read symbol B => undefined => new Response(null, { status: 500 }). Same dual-copy applied to ws.

Fix: re-export serve from @flue/runtime/node and import it (plus createNodeWebSocketTransport) through that single entry in the generated server. Mark @hono/node-server and ws external in the node-target bundler so any future imports also share the disk copy. Update dev test fixture to symlink the now-external deps so the generated server can resolve them.

Verified end-to-end: handshake 500 -> 101, SDK client streams events.

[astrobot-houston]

Thanks for the contribution! We're closing this PR and moving the conversation to the issue: #198

We've moved to a model where bugs and feature proposals are discussed in issues/discussions before code review, so the community can help prioritize and shape the work. Your branch is linked from the new thread so the implementation isn't lost — please join us there to continue the conversation.

— astrobot 🤖