feat(dag_engine): /api/dags devuelve last_runs[] (max 5) + gitlink UI badges

- executor.go: DagInfo anade LastRuns []store.DagRun. Pobla con e.store.ListRuns(name, 5, 0).
- cpp/apps/dag_engine_ui: gitlink al SHA con 5 puntitos R1..R5 via data_table BadgeRule.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

apps/dag_engine/executor.go

@@ -326,14 +326,15 @@ func generateID() string {
 
 // DagInfo summarizes a DAG file for listing.
 type DagInfo struct {
-	Name        string   `json:"name"`
-	Description string   `json:"description,omitempty"`
-	Schedule    []string `json:"schedule,omitempty"`
-	Tags        []string `json:"tags,omitempty"`
-	Type        string   `json:"type,omitempty"`
-	FilePath    string   `json:"file_path"`
-	Valid       bool     `json:"valid"`
-	LastRun     *store.DagRun `json:"last_run,omitempty"`
+	Name        string          `json:"name"`
+	Description string          `json:"description,omitempty"`
+	Schedule    []string        `json:"schedule,omitempty"`
+	Tags        []string        `json:"tags,omitempty"`
+	Type        string          `json:"type,omitempty"`
+	FilePath    string          `json:"file_path"`
+	Valid       bool            `json:"valid"`
+	LastRun     *store.DagRun   `json:"last_run,omitempty"`
+	LastRuns    []store.DagRun  `json:"last_runs,omitempty"` // 5 mas recientes (mas reciente primero)
 }
 
 // ListDAGs scans a directory for YAML files and returns parsed DAG info.
@@ -379,10 +380,11 @@ func (e *Executor) ListDAGs() ([]DagInfo, error) {
 			Valid:       true,
 		}
 
-		// Attach last run info.
-		runs, _, _ := e.store.ListRuns(dag.Name, 1, 0)
+		// Attach last 5 runs (most recent first).
+		runs, _, _ := e.store.ListRuns(dag.Name, 5, 0)
 		if len(runs) > 0 {
 			info.LastRun = &runs[0]
+			info.LastRuns = runs
 		}
 
 		dags = append(dags, info)