Add shell script showing how change TTY colors (#920)

## What are the changes about?

What was discussed in !912 before I accidentally caused it to auto merge (still not sure how that happened). I assume this is what was meant when asking for it to be in the startup script commented out.

## What existing issue does this resolve?

N/A

## Pre-requisites

- [x] I have tested & confirmed the changes work locally

Reviewed-on: https://codeberg.org/fairyglade/ly/pulls/920
Reviewed-by: AnErrupTion <anerruption@disroot.org>
Co-authored-by: hynak <hynak@noreply.codeberg.org>
Co-committed-by: hynak <hynak@noreply.codeberg.org>

build.zig

@@ -198,6 +198,8 @@ fn install_ly(allocator: std.mem.Allocator, patch_map: PatchMap, install_config:
         const patched_setup = try patchFile(allocator, "res/setup.sh", patch_map);
         try installText(patched_setup, config_dir, ly_config_directory, "setup.sh", .{ .mode = 0o755 });
 
+        try installFile("res/startup.sh", config_dir, ly_config_directory, "startup.sh", .{ .override_mode = 0o755 });
+
         try installFile("res/example.dur", config_dir, ly_config_directory, "example.dur", .{ .override_mode = 0o755 });
     }
 

res/config.ini

@@ -337,8 +337,8 @@ sleep_cmd = null
 sleep_key = F3
 
 # Command executed when starting Ly (before the TTY is taken control of)
-# If null, no command will be executed
-start_cmd = null
+# See file at path below for an example of changing the default TTY colors
+start_cmd = $CONFIG_DIRECTORY/ly/startup.sh
 
 # Center the session name.
 text_in_center = false

res/startup.sh

@@ -0,0 +1,38 @@
+#!/bin/sh
+# This file is executed when starting Ly (before the TTY is taken control of)
+# Custom startup code can be placed in this file or the start_cmd var can be pointed to a different file
+
+
+# Uncomment the example below for an example of changing the default TTY colors to an alternitive palette on linux
+# Colors are in red/green/blue hex (the current colors are a brighter palette than default)
+#
+#if [ "$TERM" = "linux" ]; then
+#	declare -a colors=(
+#		[0]="232323"  # black
+#		[1]="D75F5F"  # dark red
+#		[2]="87AF5F"  # dark green
+#		[3]="D7AF87"  # dark yellow
+#		[4]="8787AF"  # dark blue
+#		[5]="BD53A5"  # dark magenta
+#		[6]="5FAFAF"  # dark cyan
+#		[7]="E5E5E5"  # light gray
+#		[8]="2B2B2B"  # dark gray
+#		[9]="E33636"  # red
+#		[10]="98E34D" # green
+#		[11]="FFD75F" # yellow
+#		[12]="7373C9" # blue
+#		[13]="D633B2" # magenta
+#		[14]="44C9C9" # cyan
+#		[15]="FFFFFF" # white
+#	)
+#	
+#	control_palette_str="\e]P"
+#	
+#	for i in ${!colors[@]}
+#	do
+#		echo -en "${control_palette_str}$( printf "%x" ${i} )${colors[i]}"
+#	done
+#
+#	clear # for fixing background artifacting after changing color
+#fi
+