feat(storage): support deleting backends and improve admin UI

- Implement storage backend deletion, which automatically resets default storage settings and user-specific overrides when a backend is removed.
- Add unit tests covering the delete action and its cleanup side effects.
- Improve admin UI responsiveness, fixing table scrolling, flex wrapping, and text truncation for long storage backend names.
- Update security documentation to clarify trusted proxy configurations and explain how trusted proxies are protected from automatic bans.

backend/static/css/60-storage.css

@@ -23,6 +23,7 @@
 
 .storage-card-header {
   display: flex;
+  min-width: 0;
   align-items: center;
   justify-content: space-between;
   gap: 1rem;
@@ -56,6 +57,10 @@
 
 .storage-card-name {
   display: block;
+  max-width: 100%;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  white-space: nowrap;
   font-size: 0.95rem;
   font-weight: 650;
   color: var(--foreground);
@@ -82,9 +87,15 @@
   flex-wrap: wrap;
 }
 
+.storage-card-actions form {
+  min-width: 0;
+  margin: 0;
+}
+
 /* View-mode summary */
 .storage-card-summary {
   display: flex;
+  min-width: 0;
   flex-wrap: wrap;
   gap: 0 1.75rem;
   padding: 0.65rem 1.1rem 0.9rem;
@@ -96,6 +107,7 @@
   flex-direction: column;
   gap: 0.15rem;
   min-width: 8rem;
+  max-width: 100%;
 }
 
 .storage-detail > span:first-child,
@@ -137,6 +149,14 @@
   align-items: end;
 }
 
+.storage-card-fields > *,
+.storage-ops-grid > *,
+.storage-result-row,
+.storage-result-row summary > *,
+.storage-result-detail > * {
+  min-width: 0;
+}
+
 .storage-card-fields label {
   display: grid;
   gap: 0.28rem;