Stop two dialogs going see-through in dark mode

--bg-card is deliberately translucent in dark mode (rgba(0,0,61,0.4)) so cards
glass over the page; --bg-card-solid exists for the things that must not. Two
hand-rolled modal panels used the former, leaving the notification-type and
access-protocol editors transparent over the overlay with the table legible
through them. The shared .modal in style.css already got this right.

Also writes down the page-vs-modal rule the codebase already follows, since
nothing stated it: a record with a detail page gets a routed form page, a lookup
row that only exists inside its list gets a modal over that list. Plus the modal
rules from the overlay-close fix - data entry never closes on a stray click,
confirmations may, and panels are painted solid.

plugins/computers/frontend/views/AccessProtocolsList.vue

@@ -192,7 +192,9 @@ onMounted(load)
   z-index: 1000;
 }
 .modal-panel {
-  background: var(--bg-card);
+  /* Solid: var(--bg-card) is translucent in dark mode, which made this
+     dialog see-through. */
+  background: var(--bg-card-solid);
   color: var(--text);
   border: 1px solid var(--border);
   border-radius: 10px;