feat: keyboard waves A/B — global shortcut registry, question row machine, Esc-cancel dictation

Wave A (owner key map): registry in src/core/keyboard.ts + KeyboardShortcuts
provider; Cmd+D dictation, Cmd+K model picker, Shift+Tab thinking cycle,
Cmd+B sidebar, Cmd+Shift+F sessions search, Alt+arrows session cycle,
Alt+Enter open, Cmd+G graph, Cmd+N new, F2 rename, ? cheat sheet. Tab
fully suppressed; Esc chain popover > dictation > abort (local stream).
Esc now CANCELS dictation (discard) — flush stays on Cmd+D/Stop. Owner
bug reports fixed: focus outline removed, Alt+Enter setState-in-render,
Cmd+F graph node search (surface-scoped lh:kbd-find).

Wave B: question dock row machine — arrows walk options + dont-know/Other
with wrap + ring highlight, Space picks (mirrors click semantics), Enter
submits when canSubmit; typing surfaces and in-dock keys keep native
behavior. aria-checked={isSel} restored on option buttons.

docs/keyboard.md records the full map.

components/sidebar.tsx

@@ -345,11 +345,11 @@ function SessionsSidebar() {
 			cycle(1);
 		};
 		const onOpenSelected = () => {
-			setKbdIndex((i) => {
-				const target = i !== null ? shown?.[i] : undefined;
-				if (target) router.push(`/chat/${target.id}`);
-				return target ? null : i;
-			});
+			const target = kbdIndex !== null ? shown?.[kbdIndex] : undefined;
+			if (target) {
+				router.push(`/chat/${target.id}`);
+				setKbdIndex(null);
+			}
 		};
 		window.addEventListener("lh:kbd-cycle-session-prev", onPrev);
 		window.addEventListener("lh:kbd-cycle-session-next", onNext);
@@ -359,7 +359,9 @@ function SessionsSidebar() {
 			window.removeEventListener("lh:kbd-cycle-session-next", onNext);
 			window.removeEventListener("lh:kbd-open-session", onOpenSelected);
 		};
-	}, [open, toggle, shown, router]);
+		// kbdIndex is read (not upserted) so Alt+Enter pushes OUTSIDE any
+		// state updater — a router.push inside one is setState-in-render.
+	}, [open, toggle, shown, router, kbdIndex]);
 
 	// Keep the kbd-selected row in view (the rows are the container's only
 	// buttons, so the index matches).