Standardize modal overlay styles across app

Use consistent bg-gray-900/60 backdrop-blur-sm for all modal overlays,
replacing the mix of bg-black/30, bg-black/60, and bg-gray-500/75 that
existed across different components.

Updated components:
- modal.ex (reusable modal component)
- mfa_component (MFA dialogs)
- rerun_job_component, run_live/components
- React modals: AlertDialog, ConfigureAdaptorModal, GitHubSyncModal,
  WebhookAuthMethodModal, AdaptorSelectionModal

Author: elias-ba

assets/js/collaborative-editor/components/AdaptorSelectionModal.tsx

@@ -182,7 +182,7 @@ export function AdaptorSelectionModal({
     <Dialog open={isOpen} onClose={onClose} className="relative z-50">
       <DialogBackdrop
         transition
-        className="fixed inset-0 bg-gray-500/75 transition-opacity
+        className="fixed inset-0 bg-gray-900/60 backdrop-blur-sm transition-opacity
         data-closed:opacity-0 data-enter:duration-300
         data-enter:ease-out data-leave:duration-200
         data-leave:ease-in"

assets/js/collaborative-editor/components/AlertDialog.tsx

@@ -52,7 +52,7 @@ export function AlertDialog({
     <Dialog open={isOpen} onClose={onClose} className="relative z-50">
       <DialogBackdrop
         transition
-        className="fixed inset-0 bg-gray-500/75 transition-opacity
+        className="fixed inset-0 bg-gray-900/60 backdrop-blur-sm transition-opacity
         data-closed:opacity-0 data-enter:duration-300 data-enter:ease-out
         data-leave:duration-200 data-leave:ease-in"
       />

assets/js/collaborative-editor/components/ConfigureAdaptorModal.tsx

@@ -369,7 +369,7 @@ export function ConfigureAdaptorModal({
       <Dialog open={isOpen} onClose={onClose} className="relative z-50">
         <DialogBackdrop
           transition
-          className="fixed inset-0 bg-black/30 transition-opacity
+          className="fixed inset-0 bg-gray-900/60 backdrop-blur-sm transition-opacity
           data-closed:opacity-0 data-enter:duration-300
           data-enter:ease-out data-leave:duration-200
           data-leave:ease-in"

assets/js/collaborative-editor/components/GitHubSyncModal.tsx

@@ -85,7 +85,7 @@ export function GitHubSyncModal() {
     >
       <DialogBackdrop
         transition
-        className="fixed inset-0 bg-gray-500/75 transition-opacity
+        className="fixed inset-0 bg-gray-900/60 backdrop-blur-sm transition-opacity
         data-closed:opacity-0 data-enter:duration-300 data-enter:ease-out
         data-leave:duration-200 data-leave:ease-in"
       />

assets/js/collaborative-editor/components/inspector/WebhookAuthMethodModal.tsx

@@ -73,7 +73,7 @@ export function WebhookAuthMethodModal({
     <Dialog open={true} onClose={onClose} className="relative z-50">
       <DialogBackdrop
         transition
-        className="fixed inset-0 bg-gray-500/75 transition-opacity
+        className="fixed inset-0 bg-gray-900/60 backdrop-blur-sm transition-opacity
           data-closed:opacity-0 data-enter:duration-300
           data-enter:ease-out data-leave:duration-200 data-leave:ease-in"
       />

lib/lightning_web/live/components/modal.ex

@@ -40,7 +40,7 @@ defmodule LightningWeb.Components.Modal do
     >
       <div
         id={"#{@id}-bg"}
-        class="hidden fixed inset-0 bg-black/60 transition-opacity"
+        class="hidden fixed inset-0 bg-gray-900/60 backdrop-blur-sm transition-opacity"
         aria-hidden="true"
         phx-click={
           @close_on_click_away &&

lib/lightning_web/live/profile_live/mfa_component.html.heex

@@ -61,7 +61,7 @@
     >
       <div
         id="disable-mfa-modal-bg"
-        class="fixed inset-0 bg-gray-500/75 transition-opacity"
+        class="fixed inset-0 bg-gray-900/60 backdrop-blur-sm transition-opacity"
       >
       </div>
 
@@ -199,7 +199,7 @@
       >
         <div
           id="mfa-secret-modal-bg"
-          class="fixed inset-0 bg-gray-500/75 transition-opacity"
+          class="fixed inset-0 bg-gray-900/60 backdrop-blur-sm transition-opacity"
         >
         </div>
 

lib/lightning_web/live/run_live/components.ex

@@ -577,7 +577,10 @@ defmodule LightningWeb.RunLive.Components do
       phx-mounted={@show && show_modal(@id)}
       phx-remove={hide_modal(@id)}
     >
-      <div id={"#{@id}-bg"} class="fixed inset-0 bg-gray-500/75 transition-opacity">
+      <div
+        id={"#{@id}-bg"}
+        class="fixed inset-0 bg-gray-900/60 backdrop-blur-sm transition-opacity"
+      >
       </div>
 
       <div

lib/lightning_web/live/run_live/rerun_job_component.ex

@@ -75,7 +75,10 @@ defmodule LightningWeb.RunLive.RerunJobComponent do
       phx-mounted={@show && show_modal(@id)}
       phx-remove={hide_modal(@id)}
     >
-      <div id={"#{@id}-bg"} class="fixed inset-0 bg-gray-500/75 transition-opacity">
+      <div
+        id={"#{@id}-bg"}
+        class="fixed inset-0 bg-gray-900/60 backdrop-blur-sm transition-opacity"
+      >
       </div>
 
       <div