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/Arcoiris

@@ -0,0 +1,22 @@
+palette = 0=#333333
+palette = 1=#da2700
+palette = 2=#12c258
+palette = 3=#ffc656
+palette = 4=#518bfc
+palette = 5=#e37bd9
+palette = 6=#63fad5
+palette = 7=#bab2b2
+palette = 8=#777777
+palette = 9=#ffb9b9
+palette = 10=#e3f6aa
+palette = 11=#ffddaa
+palette = 12=#b3e8f3
+palette = 13=#cbbaf9
+palette = 14=#bcffc7
+palette = 15=#efefef
+background = #201f1e
+foreground = #eee4d9
+cursor-color = #872929
+cursor-text = #fffbf2
+selection-background = #25524a
+selection-foreground = #f3fffd