refactor: use __fish_palette in small utility functions (1/2)

37 duplicated declarations replaced by 8 calls. Output strings untouched;
byte-identical across 29 harness cases.

functions/edit.fish

@@ -45,12 +45,7 @@
 #   edit --editor=code --clipboard
 #   edit --text="hello world"
 function edit --description 'Open files in a terminal or GUI editor with fallbacks'
-    set -l c_head (set_color --bold cyan)
-    set -l c_cmd (set_color --bold)
-    set -l c_flag (set_color yellow)
-    set -l c_err (set_color red)
-    set -l c_dim (set_color brblack)
-    set -l c_reset (set_color normal)
+    __fish_palette
 
     # Opinionated guard (C1): fall back to the legacy bare-editor behavior.
     if not __fish_config_op_enabled (status current-function)