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/Mellow

@@ -0,0 +1,22 @@
+palette = 0=#27272a
+palette = 1=#f5a191
+palette = 2=#90b99f
+palette = 3=#e6b99d
+palette = 4=#aca1cf
+palette = 5=#e29eca
+palette = 6=#ea83a5
+palette = 7=#c1c0d4
+palette = 8=#424246
+palette = 9=#ffae9f
+palette = 10=#9dc6ac
+palette = 11=#f0c5a9
+palette = 12=#b9aeda
+palette = 13=#ecaad6
+palette = 14=#f591b2
+palette = 15=#cac9dd
+background = #161617
+foreground = #c9c7cd
+cursor-color = #cac9dd
+cursor-text = #161617
+selection-background = #2a2a2d
+selection-foreground = #c1c0d4