fix(server): bound stale websocket connections

Track application ownership per physical socket and terminate abandoned or backpressured transports without disrupting replacement connections.

packages/client/src/daemon-client.test.ts

@@ -664,6 +664,7 @@ test("advertises client capabilities in hello", async () => {
     clientType: "cli",
     protocolVersion: 1,
     capabilities: {
+      application_socket_lease: true,
       custom_mode_icons: true,
       project_updates: true,
       provider_subagents: true,

packages/client/src/daemon-client.ts

@@ -5151,6 +5151,7 @@ export class DaemonClient {
             [CLIENT_CAPS.providerSubagents]: true,
             [CLIENT_CAPS.projectUpdates]: true,
             ...this.config.capabilities,
+            [CLIENT_CAPS.applicationSocketLease]: true,
           },
           ...(this.config.appVersion ? { appVersion: this.config.appVersion } : {}),
         }),