libghostty(formatter): enable kitty gfx for vt

This adds support for printing kitty graphics using the `terminal.Formatter` through a new
`terminal.ScreenFormatter.Extra` option `kitty_graphics`.

This only implements kitty gfx for the `vt` format option.

References: https://discord.com/channels/1005603569187160125/1420009803173859449/1446588699952287849

Author: ericbower-sdx

src/terminal/c/formatter.zig

@@ -37,6 +37,7 @@ pub const ScreenOptions = extern struct {
         hyperlink: bool,
         protection: bool,
         kitty_keyboard: bool,
+        kitty_graphics: bool,
         charsets: bool,
 
         comptime {
@@ -53,6 +54,7 @@ pub const ScreenOptions = extern struct {
                 .hyperlink = self.hyperlink,
                 .protection = self.protection,
                 .kitty_keyboard = self.kitty_keyboard,
+                .kitty_graphics = self.kitty_graphics,
                 .charsets = self.charsets,
             };
         }
@@ -232,7 +234,7 @@ test "terminal_new/free" {
         &lib.alloc.test_allocator,
         &f,
         t,
-        .{ .emit = .plain, .unwrap = false, .trim = true, .extra = .{ .palette = false, .modes = false, .scrolling_region = false, .tabstops = false, .pwd = false, .keyboard = false, .screen = .{ .cursor = false, .style = false, .hyperlink = false, .protection = false, .kitty_keyboard = false, .charsets = false } } },
+        .{ .emit = .plain, .unwrap = false, .trim = true, .extra = .{ .palette = false, .modes = false, .scrolling_region = false, .tabstops = false, .pwd = false, .keyboard = false, .screen = .{ .cursor = false, .style = false, .hyperlink = false, .protection = false, .kitty_keyboard = false, .kitty_graphics = false, .charsets = false } } },
     ));
     try testing.expect(f != null);
     free(f);
@@ -244,7 +246,7 @@ test "terminal_new invalid_value on null terminal" {
         &lib.alloc.test_allocator,
         &f,
         null,
-        .{ .emit = .plain, .unwrap = false, .trim = true, .extra = .{ .palette = false, .modes = false, .scrolling_region = false, .tabstops = false, .pwd = false, .keyboard = false, .screen = .{ .cursor = false, .style = false, .hyperlink = false, .protection = false, .kitty_keyboard = false, .charsets = false } } },
+        .{ .emit = .plain, .unwrap = false, .trim = true, .extra = .{ .palette = false, .modes = false, .scrolling_region = false, .tabstops = false, .pwd = false, .keyboard = false, .screen = .{ .cursor = false, .style = false, .hyperlink = false, .protection = false, .kitty_keyboard = false, .kitty_graphics = false, .charsets = false } } },
     ));
     try testing.expect(f == null);
 }
@@ -269,7 +271,7 @@ test "format plain" {
         &lib.alloc.test_allocator,
         &f,
         t,
-        .{ .emit = .plain, .unwrap = false, .trim = true, .extra = .{ .palette = false, .modes = false, .scrolling_region = false, .tabstops = false, .pwd = false, .keyboard = false, .screen = .{ .cursor = false, .style = false, .hyperlink = false, .protection = false, .kitty_keyboard = false, .charsets = false } } },
+        .{ .emit = .plain, .unwrap = false, .trim = true, .extra = .{ .palette = false, .modes = false, .scrolling_region = false, .tabstops = false, .pwd = false, .keyboard = false, .screen = .{ .cursor = false, .style = false, .hyperlink = false, .protection = false, .kitty_keyboard = false, .kitty_graphics = false, .charsets = false } } },
     ));
     defer free(f);
 
@@ -295,7 +297,7 @@ test "format reflects terminal changes" {
         &lib.alloc.test_allocator,
         &f,
         t,
-        .{ .emit = .plain, .unwrap = false, .trim = true, .extra = .{ .palette = false, .modes = false, .scrolling_region = false, .tabstops = false, .pwd = false, .keyboard = false, .screen = .{ .cursor = false, .style = false, .hyperlink = false, .protection = false, .kitty_keyboard = false, .charsets = false } } },
+        .{ .emit = .plain, .unwrap = false, .trim = true, .extra = .{ .palette = false, .modes = false, .scrolling_region = false, .tabstops = false, .pwd = false, .keyboard = false, .screen = .{ .cursor = false, .style = false, .hyperlink = false, .protection = false, .kitty_keyboard = false, .kitty_graphics = false, .charsets = false } } },
     ));
     defer free(f);
 
@@ -327,7 +329,7 @@ test "format null returns required size" {
         &lib.alloc.test_allocator,
         &f,
         t,
-        .{ .emit = .plain, .unwrap = false, .trim = true, .extra = .{ .palette = false, .modes = false, .scrolling_region = false, .tabstops = false, .pwd = false, .keyboard = false, .screen = .{ .cursor = false, .style = false, .hyperlink = false, .protection = false, .kitty_keyboard = false, .charsets = false } } },
+        .{ .emit = .plain, .unwrap = false, .trim = true, .extra = .{ .palette = false, .modes = false, .scrolling_region = false, .tabstops = false, .pwd = false, .keyboard = false, .screen = .{ .cursor = false, .style = false, .hyperlink = false, .protection = false, .kitty_keyboard = false, .kitty_graphics = false, .charsets = false } } },
     ));
     defer free(f);
 
@@ -359,7 +361,7 @@ test "format buffer too small" {
         &lib.alloc.test_allocator,
         &f,
         t,
-        .{ .emit = .plain, .unwrap = false, .trim = true, .extra = .{ .palette = false, .modes = false, .scrolling_region = false, .tabstops = false, .pwd = false, .keyboard = false, .screen = .{ .cursor = false, .style = false, .hyperlink = false, .protection = false, .kitty_keyboard = false, .charsets = false } } },
+        .{ .emit = .plain, .unwrap = false, .trim = true, .extra = .{ .palette = false, .modes = false, .scrolling_region = false, .tabstops = false, .pwd = false, .keyboard = false, .screen = .{ .cursor = false, .style = false, .hyperlink = false, .protection = false, .kitty_keyboard = false, .kitty_graphics = false, .charsets = false } } },
     ));
     defer free(f);
 
@@ -392,7 +394,7 @@ test "format vt" {
         &lib.alloc.test_allocator,
         &f,
         t,
-        .{ .emit = .vt, .unwrap = false, .trim = true, .extra = .{ .palette = true, .modes = false, .scrolling_region = false, .tabstops = false, .pwd = false, .keyboard = false, .screen = .{ .cursor = false, .style = true, .hyperlink = true, .protection = false, .kitty_keyboard = false, .charsets = false } } },
+        .{ .emit = .vt, .unwrap = false, .trim = true, .extra = .{ .palette = true, .modes = false, .scrolling_region = false, .tabstops = false, .pwd = false, .keyboard = false, .screen = .{ .cursor = false, .style = true, .hyperlink = true, .protection = false, .kitty_keyboard = false, .kitty_graphics = false, .charsets = false } } },
     ));
     defer free(f);
 
@@ -437,7 +439,7 @@ test "format plain with selection" {
         &lib.alloc.test_allocator,
         &f,
         t,
-        .{ .emit = .plain, .unwrap = false, .trim = true, .selection = &sel, .extra = .{ .palette = false, .modes = false, .scrolling_region = false, .tabstops = false, .pwd = false, .keyboard = false, .screen = .{ .cursor = false, .style = false, .hyperlink = false, .protection = false, .kitty_keyboard = false, .charsets = false } } },
+        .{ .emit = .plain, .unwrap = false, .trim = true, .selection = &sel, .extra = .{ .palette = false, .modes = false, .scrolling_region = false, .tabstops = false, .pwd = false, .keyboard = false, .screen = .{ .cursor = false, .style = false, .hyperlink = false, .protection = false, .kitty_keyboard = false, .kitty_graphics = false, .charsets = false } } },
     ));
     defer free(f);
 
@@ -463,7 +465,7 @@ test "format html" {
         &lib.alloc.test_allocator,
         &f,
         t,
-        .{ .emit = .html, .unwrap = false, .trim = true, .extra = .{ .palette = false, .modes = false, .scrolling_region = false, .tabstops = false, .pwd = false, .keyboard = false, .screen = .{ .cursor = false, .style = false, .hyperlink = false, .protection = false, .kitty_keyboard = false, .charsets = false } } },
+        .{ .emit = .html, .unwrap = false, .trim = true, .extra = .{ .palette = false, .modes = false, .scrolling_region = false, .tabstops = false, .pwd = false, .keyboard = false, .screen = .{ .cursor = false, .style = false, .hyperlink = false, .protection = false, .kitty_keyboard = false, .kitty_graphics = false, .charsets = false } } },
     ));
     defer free(f);