Summary

On Windows the crossterm console backend delivers both Press and Release (and Repeat) KeyEventKind variants for every keystroke. The TUI's terminal reader was forwarding every Event::Key it read, and the two dispatch sites in ui_loop.rs called handle_key_event without inspecting KeyEventKind. Toggle bindings (h/1 Help, A alerts, M topology mode, sort keys, T/V tab jumps) therefore fired on Press and then immediately undid themselves on Release — the "flash" symptom that made the TUI effectively unusable on Windows.

Root cause

crossterm reports keyboard events differently per platform:

• Unix (without keyboard-enhancement flags, which all-smi does not enable): only KeyEventKind::Press is delivered. Holding a key produces repeated Press via the terminal's own auto-repeat.
• Windows: the console backend additionally delivers Release and Repeat.

A single h press on Windows therefore produced Press → show_help = true, then Release → show_help = false. Net effect: the help page appeared and instantly disappeared.

Fix

Filter at the single chokepoint in src/view/ui_events.rs::terminal_reader_loop so both consumers — the live next_event() path and the drain_pending_events() batch path — are protected by one guard. The predicate is extracted into a small is_actionable_key_event(KeyEventKind) -> bool helper so it is unit-testable without a live terminal.

if let Event::Key(k) = &evt
    && !is_actionable_key_event(k.kind)
{
    continue;
}

No change in src/view/event_handler.rs — its dispatch logic is already correct once Release is filtered upstream. The change is a no-op on Unix.

Test plan

• cargo fmt --check
• cargo check --lib --tests
• cargo clippy --lib --tests -- -D warnings
• cargo test --bin all-smi view::ui_events::tests (20 passed, 0 failed; 6 new regression tests)
• Manual Windows verification: h/1 opens and holds Help, A/M toggle cleanly, navigation moves once per press
• Manual macOS/Linux verification: no behavioral regression

New regression tests (all in src/view/ui_events.rs)

• test_is_actionable_key_event_accepts_press
• test_is_actionable_key_event_rejects_release
• test_is_actionable_key_event_rejects_repeat
• test_reader_filter_drops_release_events
• test_reader_filter_passes_press_events
• test_reader_filter_passes_non_key_events

Closes #212