Restore macOS direct LAN connections (#3071)

* fix(desktop): restore direct LAN connections

Desktop 0.3.0 routed remote WebSockets through the Electron main process, causing previously working macOS LAN connections to fail with EHOSTUNREACH. Revert custom direct headers and restore the renderer WebSocket path used before the regression.

* fix(app): replace host connections by identity

Keep one connection per stable ID when TLS or password settings change. This preserves the current-main upsert invariant while the custom-header rollback removes the unrelated transport feature.

packages/protocol/src/host-connection-schema.ts

@@ -6,7 +6,6 @@ export const DirectTcpHostConnectionSchema = z.object({
   endpoint: z.string(),
   useTls: z.boolean().optional().default(false),
   password: z.string().optional(),
-  headers: z.record(z.string(), z.string()).optional(),
 });
 
 export type DirectTcpHostConnection = z.input<typeof DirectTcpHostConnectionSchema>;