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/Square

@@ -0,0 +1,22 @@
+palette = 0=#050505
+palette = 1=#e9897c
+palette = 2=#b6377d
+palette = 3=#ecebbe
+palette = 4=#a9cdeb
+palette = 5=#75507b
+palette = 6=#c9caec
+palette = 7=#f2f2f2
+palette = 8=#474747
+palette = 9=#f99286
+palette = 10=#c3f786
+palette = 11=#fcfbcc
+palette = 12=#b6defb
+palette = 13=#ad7fa8
+palette = 14=#d7d9fc
+palette = 15=#e2e2e2
+background = #1a1a1a
+foreground = #acacab
+cursor-color = #fcfbcc
+cursor-text = #000000
+selection-background = #4d4d4d
+selection-foreground = #ffffff