feat(resources): bundle color themes and compiled xterm-ghostty terminfo

Makes the resources directory self-contained like Ghostty's share/ghostty:
- themes/: the 463 iTerm2-Color-Schemes themes Ghostty 1.3.1 ships
  (release 20260216-151611-fc73ce3), with the upstream MIT license.
- terminfo/: xterm-ghostty compiled with `tic -x` from the terminfo
  source generated by ghostty-termio; `infocmp -x` is identical to the
  installed Ghostty's entry.

The generator script and resources-dir discovery changes follow in a
separate commit.

Test Plan:
- TERMINFO=resources/terminfo infocmp -x xterm-ghostty

resources/themes/Retro

@@ -0,0 +1,22 @@
+palette = 0=#13a10e
+palette = 1=#13a10e
+palette = 2=#13a10e
+palette = 3=#13a10e
+palette = 4=#13a10e
+palette = 5=#13a10e
+palette = 6=#13a10e
+palette = 7=#13a10e
+palette = 8=#16ba10
+palette = 9=#16ba10
+palette = 10=#16ba10
+palette = 11=#16ba10
+palette = 12=#16ba10
+palette = 13=#16ba10
+palette = 14=#16ba10
+palette = 15=#16ba10
+background = #000000
+foreground = #13a10e
+cursor-color = #13a10e
+cursor-text = #000000
+selection-background = #ffffff
+selection-foreground = #000000