Move the screen types out of pardes.zig into surface.zig

Pure move: Color, FontRole, CellStyle, Cell, AsciiDiff, PanelCellDiff,
ImageCacheKey, NativePlacement, ImagePatch, ImagePlace and Surface, with
their eight tests, go verbatim to the new surface.zig with the imports they
use. pardes.zig keeps one `pub const X = @import("surface.zig").X;` line
per type, as it already does for Pane, Rect and the tag layers, so the
shells' `pardes.Cell` / `pardes.Surface` spellings do not change.
Surface.print, clearRect and overlayDash become pub because render calls
them from pardes.zig. surface.zig is added to pardes.zig's test block and
to the embedded source list.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

1 files changed, 1 insertions, 0 deletions

diff --git a/src/fs.zig b/src/fs.zig
index 3dccdf7f..e1fe0b9c 100644
--- a/src/fs.zig
+++ b/src/fs.zig
@@ -36,6 +36,7 @@ else
 const source_files = [_]Source{
     .{ .path = "src/pardes.zig", .contents = @embedFile("pardes.zig") },
     .{ .path = "src/panes.zig", .contents = @embedFile("panes.zig") },
+    .{ .path = "src/surface.zig", .contents = @embedFile("surface.zig") },
     .{ .path = "src/File.zig", .contents = @embedFile("File.zig") },
     .{ .path = "src/Output.zig", .contents = @embedFile("Output.zig") },
     .{ .path = "src/Mini.zig", .contents = @embedFile("Mini.zig") },