fix(tui): only cycle history at input boundaries on arrows

Follow-up on #13726 from blitz feedback: Up/Down history cycling should only trigger when the caret is at the start/end boundary (or the input is empty).\n\nPreviously useInputHandlers intercepted arrows whenever inputBuf was empty, which still stole Up/Down from normal multiline editing. textInput now publishes caret position through inputSelectionStore even with no active selection, and useInputHandlers gates history/queue cycling on those boundaries.

ui-tui/src/app/useInputHandlers.ts

@@ -288,15 +288,27 @@ export function useInputHandlers(ctx: InputHandlerContext): InputHandlerResult {
     }
 
     if (key.upArrow && !cState.inputBuf.length) {
-      cycleQueue(1) || cycleHistory(-1)
+      const inputSel = getInputSelection()
+      const atStart = !cState.input || (!!inputSel && inputSel.start === 0 && inputSel.end === 0)
 
-      return
+      if (atStart) {
+        cycleQueue(1) || cycleHistory(-1)
+
+        return
+      }
     }
 
     if (key.downArrow && !cState.inputBuf.length) {
-      cycleQueue(-1) || cycleHistory(1)
+      const inputSel = getInputSelection()
+      const atEnd =
+        !cState.input ||
+        (!!inputSel && inputSel.start === cState.input.length && inputSel.end === cState.input.length)
 
-      return
+      if (atEnd || cState.historyIdx !== null) {
+        cycleQueue(-1) || cycleHistory(1)
+
+        return
+      }
     }
 
     if (isAction(key, ch, 'c')) {

ui-tui/src/components/textInput.tsx

@@ -400,22 +400,20 @@ export function TextInput({
       return
     }
 
-    if (selected) {
-      setInputSelection({
-        clear: () => {
+    setInputSelection({
+      clear: () => {
+        if (selRef.current) {
           selRef.current = null
           setSel(null)
-        },
-        end: selected.end,
-        start: selected.start,
-        value: vRef.current
-      })
-    } else {
-      setInputSelection(null)
-    }
+        }
+      },
+      end: selected?.end ?? curRef.current,
+      start: selected?.start ?? curRef.current,
+      value: vRef.current
+    })
 
     return () => setInputSelection(null)
-  }, [focus, selected])
+  }, [cur, focus, selected])
 
   useEffect(
     () => () => {