feat: implement selection-first multi-target editing

src/main.rs

@@ -11,9 +11,13 @@ Normal: i/a insert, I/A insert at first nonblank/end, o/O new line
         h/j/k/l move, 0/$ line ends, x delete, J join lines
         w/b/e word next/previous/end, W/B/E whitespace-delimited WORDs
         u undo, U redo, : command, / search, n/N next/previous match
-        v select, p/P paste after/before cursor
-Visual: motions extend selection, y copy, d/x/Delete cut, c change, v/Esc cancel
-Insert: Esc returns to normal
+        v select, p/P paste fragments, Ctrl+k/Ctrl+e clone above/below
+        Esc keeps only the primary caret
+Visual: motions extend selections, y copy, d/x/Delete cut, c change
+        I/A insert at each selected line's first nonblank/end
+        Ctrl+l split rows, Ctrl+n add occurrence, Ctrl+s skip, Ctrl+a all
+        v/Esc returns to Normal retaining carets
+Insert: Esc returns to Normal retaining carets
 Search: Enter finds next literal match, Esc cancels (case-sensitive, wraps)
 Commands: :w [PATH], :q, :q!, :wq [PATH], :plugins, :PLUGIN [ARGS]