mod(renderer): initial version of double buffer intermediate renderer

This branch will implement the necessary changes for the widgets and
their implementations to use the new renderer correctly.

src/terminal.zig

@@ -20,7 +20,7 @@ pub const ReportMode = enum {
 pub fn getTerminalSize() Size {
     var ws: std.posix.winsize = undefined;
     _ = std.posix.system.ioctl(std.posix.STDIN_FILENO, std.posix.T.IOCGWINSZ, @intFromPtr(&ws));
-    return .{ .cols = ws.col, .rows = ws.row };
+    return .{ .cols = ws.col - 1, .rows = ws.row - 1 };
 }
 
 pub fn saveScreen() !void {
@@ -126,8 +126,8 @@ pub fn getCursorPosition() !Position {
     }
 
     return .{
-        .row = try std.fmt.parseInt(u16, row[0..ridx], 10),
-        .col = try std.fmt.parseInt(u16, col[0..cidx], 10),
+        .row = try std.fmt.parseInt(u16, row[0..ridx], 10) - 1,
+        .col = try std.fmt.parseInt(u16, col[0..cidx], 10) - 1,
     };
 }