Description
HandleKey case 'tea.KeyRunes, tea.KeySpace' loops over k.Runes inserting each rune, THEN an 'if k.Type == tea.KeySpace { InsertRune(" ") }' inserts another. In real bubbletea (v1.3.6 key.go) a space keypress is Key{Type:KeySpace, Runes:[' ']}, so both fire → two spaces. v1 test TestHandleKeySpaceInsertsSingleSpace missed it by sending KeySpace with empty Runes (unrealistic). Fix: drop the redundant if-block; make the test send Runes:[' '].
Acceptance Criteria
- #1 single space inserted per spacebar press in the real terminal
- #2 test sends a realistic KeySpace msg (Runes: [' '])