feat(snapshots): evolution API, tactic breakdown and dashboard trend chart [FASE-5.2]

frontend/src/api/snapshots.ts

@@ -12,10 +12,28 @@ export interface SnapshotSummary {
   not_covered_count: number;
   in_progress_count: number;
   not_evaluated_count: number;
+  coverage_percentage?: number;
+  by_tactic?: Record<string, unknown>;
+  by_status?: Record<string, number>;
+  stale_count?: number;
+  never_tested_count?: number;
   created_by: string | null;
   created_at: string | null;
 }
 
+export interface CoverageEvolutionPoint {
+  date: string | null;
+  name: string | null;
+  org_score: number;
+  coverage_pct: number;
+  by_tactic: Record<string, unknown>;
+  by_status: Record<string, number>;
+  stale_count: number;
+  never_tested_count: number;
+  validated_count: number;
+  total_techniques: number;
+}
+
 export interface TechniqueState {
   mitre_id: string;
   technique_id: string;
@@ -76,6 +94,17 @@ export async function getSnapshot(snapshotId: string): Promise<SnapshotDetail> {
   return data;
 }
 
+/** Coverage trend points for dashboard charts. */
+export async function getCoverageEvolution(
+  months = 12,
+): Promise<CoverageEvolutionPoint[]> {
+  const { data } = await client.get<CoverageEvolutionPoint[]>(
+    "/snapshots/evolution",
+    { params: { months } },
+  );
+  return data;
+}
+
 /** Compare two snapshots. */
 export async function compareSnapshots(
   aId: string,