feat: delete AI reports, Super Contexte versions, and KB entries

- database.py: add delete_ai_report(), delete_reasoning_state(), delete_kb_entry()
- reasoning.py: DELETE /api/reasoning/reports/{id}
- knowledge.py: DELETE /api/knowledge/history/{id} and /entries/{id}
- useApi.ts: useDeleteAiReport, useDeleteReasoningState, useDeleteKbEntry hooks
- RapportIA.tsx: trash icon on hover in archived reports sidebar
- SuperContexte.tsx: trash icon on hover for history versions and KB entries;
  both propagate onDelete through CategorySection down to KbEntry

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/src/hooks/useApi.ts

@@ -546,3 +546,30 @@ export const usePatchKbEntryStatus = () => {
     onSuccess: () => qc.invalidateQueries({ queryKey: ['knowledge-entries'] }),
   })
 }
+
+export const useDeleteAiReport = () => {
+  const qc = useQueryClient()
+  return useMutation({
+    mutationFn: (id: number) => api.delete(`/reasoning/reports/${id}`).then(r => r.data),
+    onSuccess: () => qc.invalidateQueries({ queryKey: ['ai-reports-list'] }),
+  })
+}
+
+export const useDeleteReasoningState = () => {
+  const qc = useQueryClient()
+  return useMutation({
+    mutationFn: (id: number) => api.delete(`/knowledge/history/${id}`).then(r => r.data),
+    onSuccess: () => {
+      qc.invalidateQueries({ queryKey: ['knowledge-history'] })
+      qc.invalidateQueries({ queryKey: ['knowledge-state'] })
+    },
+  })
+}
+
+export const useDeleteKbEntry = () => {
+  const qc = useQueryClient()
+  return useMutation({
+    mutationFn: (id: number) => api.delete(`/knowledge/entries/${id}`).then(r => r.data),
+    onSuccess: () => qc.invalidateQueries({ queryKey: ['knowledge-entries'] }),
+  })
+}