fix(art): keep iTerm2 inline images on screen

iTerm2 images live in the cell grid, unlike Kitty placements: repainting
the mosaic behind them erases the picture. Re-emit the image whenever the
mosaic identity (station + track) changes, even if the artwork bytes are
the same.

Also send doNotMoveCursor=1 to iTerm2 itself so the terminal does not
scroll or jump the cursor out from under Textual's compositor; WezTerm
keeps the previous payload since it is pickier about parameters.

tests/test_art.py

@@ -5,6 +5,7 @@ from PIL import Image
 
 from somafm_tui import artwork
 from somafm_tui.app import SomaFMApp
+from somafm_tui.widgets import art as art_widgets
 from somafm_tui.widgets.art import ArtPane, ITerm2Image, KittyImage
 from somafm_tui.widgets.stage import StagePanel
 
@@ -45,12 +46,23 @@ async def test_art_pane_switches_between_image_and_mosaic(monkeypatch) -> None:
         assert pane.render() is not None
 
 
-def test_iterm2_sequence_uses_cell_units() -> None:
+def test_iterm2_sequence_uses_cell_units(monkeypatch) -> None:
+    monkeypatch.setattr(art_widgets, "_iterm2_native", lambda: False)
     widget = ITerm2Image(Image.new("RGBA", (32, 32), (10, 20, 30, 255)))
     sequence = widget._sequence(13, 8)
     assert sequence.startswith(
         "\x1b]1337;File=inline=1;width=13;height=8;"
     )
+    # WezTerm shares the protocol but not every iTerm2-only parameter.
+    assert "doNotMoveCursor" not in sequence
+
+
+def test_iterm2_native_keeps_the_cursor_put(monkeypatch) -> None:
+    monkeypatch.setattr(art_widgets, "_iterm2_native", lambda: True)
+    widget = ITerm2Image(Image.new("RGBA", (32, 32), (10, 20, 30, 255)))
+    sequence = widget._sequence(13, 8)
+    assert sequence.startswith("\x1b]1337;File=inline=1;doNotMoveCursor=1;")
+    assert "width=13;height=8;" in sequence
 
 
 def test_kitty_direct_placement_sequences() -> None: