feat: standardize correspondent and tag types with usage count

frontend/src/correspondents/CorrespondentsPanel.tsx

@@ -1,22 +1,11 @@
 import { useCallback, useState } from 'react';
 import type { FormEvent, KeyboardEvent } from 'react';
-
-interface CorrespondentUsage {
-  total?: number;
-  [key: string]: unknown;
-}
-
-interface CorrespondentEntry {
-  id?: string;
-  name?: string;
-  usage?: CorrespondentUsage;
-  [key: string]: unknown;
-}
+import type { Correspondent } from '../types/documents';
 
 export interface CorrespondentsPanelProps {
-  correspondents?: CorrespondentEntry[];
+  correspondents?: Correspondent[];
   onRefresh?: () => void | Promise<void>;
-  onCreate: (payload: { name: string }) => Promise<CorrespondentEntry | void>;
+  onCreate: (payload: { name: string }) => Promise<Correspondent | void>;
   onUpdate: (id: string, payload: { name: string }) => Promise<void>;
   onDelete: (id: string) => Promise<void>;
   onNotify?: (message: string, variant?: string) => void;
@@ -37,7 +26,7 @@ function CorrespondentsPanel({
   const [creating, setCreating] = useState(false);
   const [deletingId, setDeletingId] = useState<string | null>(null);
 
-  const startEdit = useCallback((correspondent: CorrespondentEntry) => {
+  const startEdit = useCallback((correspondent: Correspondent) => {
     setEditingId(correspondent.id);
     setDraftName(correspondent.name);
   }, []);
@@ -68,7 +57,7 @@ function CorrespondentsPanel({
   }, [editingId, draftName, onUpdate, cancelEdit, onNotify]);
 
   const handleDelete = useCallback(
-    async (correspondent: CorrespondentEntry) => {
+    async (correspondent: Correspondent) => {
       if (!correspondent?.id) return;
       setDeletingId(correspondent.id);
       try {
@@ -121,12 +110,12 @@ function CorrespondentsPanel({
     [handleSave, cancelEdit],
   );
 
-  const renderUsage = useCallback((usage?: CorrespondentUsage) => {
-    if (!usage) {
+  const renderUsage = useCallback((correspondent: Correspondent) => {
+    const count = correspondent.usage_count;
+    if (count == null || !Number.isFinite(count)) {
       return '0';
     }
-    const total = Number.isFinite(usage.total) ? Number(usage.total) : 0;
-    return total.toString();
+    return count.toString();
   }, []);
 
   return (
@@ -195,7 +184,7 @@ function CorrespondentsPanel({
                           <span>{correspondent.name}</span>
                         )}
                       </td>
-                      <td className="numeric">{renderUsage(correspondent.usage)}</td>
+                      <td className="numeric">{renderUsage(correspondent)}</td>
                       <td className="actions">
                         {isEditing ? (
                           <div className="tags-table__edit-controls">