refactor(qconnect): share delegation lifecycle

Move authority fences, preflight, rejoin watchdogs, LAN projection, and physical runtime teardown into qconnect-app for both Qt and qbzd.

cx

crates/qconnect-app/Cargo.toml

@@ -23,6 +23,7 @@ serde = { workspace = true }
 serde_json = { workspace = true }
 thiserror = { workspace = true }
 uuid = { version = "1", features = ["v4"] }
+zeroize = "1"
 log = { workspace = true }
 
 [dev-dependencies]