config(fish): add fish completions for cli tools

dot_config/fish/functions/gdc.fish

@@ -0,0 +1,9 @@
+function gdc --description "Discard all git changes with gum confirmation"
+    if gum confirm "Discard all uncommitted changes? This is irreversible."
+        git reset --hard HEAD
+        git clean -fd
+        echo "Changes wiped."
+    else
+        echo "Operation aborted."
+    end
+end