Macros: suppress placeholder color stripes (#dedede, #fff, ...)

The bbctrl controller seeds new macros with placeholder colors like
'#dedede' and '#ffffff'. Treating those as 'configured' lit up the
asymmetric 6 px left stripe on every default macro, which looked
lopsided.

Add control-view.has_macro_color() that filters out a fixed set of
default placeholders plus anything within the near-white band
(R+G+B > 690). The .has-color class and the inline border-left-color
style are gated on that helper, so unconfigured macros render as
clean symmetric slate tiles.

Tested live on http://10.1.10.55/#control with the existing macro
config (#dedede): button now renders without the gray stripe.

src/pug/templates/control-view.pug

@@ -246,13 +246,16 @@ script#control-view-template(type="text/x-template")
             .stat-sub(v-else) Line · ETA --
 
     // ----- Macro row (slice 0..7); full list lives in Settings → Macros -----
+    // The colored left stripe (.has-color) is suppressed for white,
+    // near-white and other default placeholder colors so unconfigured
+    // macros render as clean slate tiles instead of looking lopsided.
     .macro-row(v-if="state.macros && state.macros.length")
       button.macro-btn(v-for="(index, macros) in state.macros.slice(0, 8)",
         title="Click to run macro",
         @click="run_macro(index)",
         :disabled="!is_ready",
-        :class="{'has-color': macros.color && macros.color !== '#ffffff' && macros.color !== '#fff'}",
-        :style="macros.color && macros.color !== '#ffffff' && macros.color !== '#fff' ? {borderLeftColor: macros.color} : {}")
+        :class="{'has-color': has_macro_color(macros)}",
+        :style="has_macro_color(macros) ? {borderLeftColor: macros.color} : {}")
         span.mnum {{index + 1}}
         span.mname {{macros.name || ('Macro ' + (index + 1))}}