Discovery: wide-area bridge DNS-SD

# Conflicts:
#	apps/ios/Sources/Bridge/BridgeDiscoveryModel.swift
#	src/cli/dns-cli.ts

src/cli/gateway.sigterm.test.ts

@@ -85,6 +85,9 @@ describe("gateway SIGTERM", () => {
         env: {
           ...process.env,
           CLAWDIS_SKIP_PROVIDERS: "1",
+          // Avoid port collisions with other test processes that may also start a bridge server.
+          CLAWDIS_BRIDGE_HOST: "127.0.0.1",
+          CLAWDIS_BRIDGE_PORT: "0",
         },
         stdio: ["ignore", "pipe", "pipe"],
       },