feat: implement mode 1048 for saving/restoring cursor position (#7553)

Implements mode 1048 for saving/restoring cursor position.

This is the same as mode 1049 but only saves cursor position without
touching the alternate screen.

**save/restore cursor position:**
- `ESC[?1048h` - save cursor position  
- `ESC[?1048l` - restore cursor position

**Quick test:**
```bash
printf '\e[5;10H[SAVED HERE]'
printf '\e[?1048h'                # save position
printf '\e[15;1HMoved somewhere else...'
printf '\e[?1048l'                # restore 
printf ' RESTORED!'           # should appear next to [SAVED HERE]
```

Fixes #7473

1 files changed, 12 insertions, 0 deletions

diff --git a/src/termio/stream_handler.zig b/src/termio/stream_handler.zig
index b3aa82d20..2069a8ff2 100644
--- a/src/termio/stream_handler.zig
+++ b/src/termio/stream_handler.zig
@@ -597,6 +597,18 @@ pub const StreamHandler = struct {
                 try self.queueRender();
             },
 
+            // Mode 1048 is xterm's conditional save cursor depending
+            // on if alt screen is enabled or not (at the terminal emulator
+            // level). Alt screen is always enabled for us so this just
+            // does a save/restore cursor.
+            .save_cursor => {
+                if (enabled) {
+                    self.terminal.saveCursor();
+                } else {
+                    try self.terminal.restoreCursor();
+                }
+            },
+
             // Force resize back to the window size
             .enable_mode_3 => {
                 const grid_size = self.size.grid();