fix(cli): drive single-target runs with ManagedClient

Replace the manual single-target ClientSession loops in the stream and TUI adapters with ManagedClient::start_with_subscription so the existing worker owns opening, deadline-aware pacing, receive handling, timeout polling, draining, and close.

Use bounded subscription waits for interruption and input polling, drain queued events before and after join, and report per-subscription drops without changing output, statistics, labels, summaries, warning, or peer-close policy. Add process and unit regressions for 10 ms cadence, interruption, final-event draining, TUI terminal state, and overflow visibility.

crates/irtt-cli/src/shared/client/mod.rs

@@ -8,7 +8,7 @@ pub use args::{
     ClockArg, CommonClientArgs, ReceivedStatsArg, TimestampArg,
 };
 pub use config::{expected_probe_count, DEFAULT_RECV_TIMEOUT};
-pub use session::{final_drain_duration, is_shutdown_requested, ClientSession, RECV_BUDGET};
+pub use session::is_shutdown_requested;
 pub use targets::{
     parse_labelled_target, resolved_managed_targets, target_specs, GroupPacingArg,
     LabelledTargetArg, ResolvedTarget, TargetSpec,