fix(gps-tracks): aggregate last_pipeline_run in health endpoint (REQ-F-12)

Replace raw single-row fetch with aggregation over all pipeline_runs
rows sharing the latest started_at. Returns structured object with
regions[], sources_ok[], sources_error[], tracks_added instead of
a raw DB row with region_id/source_id strings.

Returns null when no runs exist (empty DB).

Update test_i40_health_endpoint: add db_with_pipeline_runs fixture
(two rows, same started_at, two regions) and assert the full
aggregated shape including concrete values.

Refs: ET-008
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/api/gps_tracks/endpoint.py

@@ -205,7 +205,12 @@ def create_gps_router(db_path: str) -> APIRouter:
 
     @router.get("/health")
     async def gps_health():
-        """Статистика GPS-треков БД."""
+        """Статистика GPS-треков БД.
+
+        Поле last_pipeline_run агрегирует все записи pipeline_runs,
+        принадлежащие последнему запуску (по максимальному started_at).
+        Возвращает None если прогонов ещё не было.
+        """
         try:
             conn = _get_conn()
             cur = conn.cursor()
@@ -218,17 +223,52 @@ def create_gps_router(db_path: str) -> APIRouter:
             )
             by_activity = {row["activity_type"] or "other": row["cnt"] for row in cur.fetchall()}
 
+            # REQ-F-12: агрегированный объект по всем строкам последнего прогона.
+            # Все строки одного запуска pipeline имеют одинаковый started_at —
+            # pipeline устанавливает его перед итерацией по (region, source).
             cur.execute(
                 """
-                SELECT id, started_at, finished_at, region_id, source_id,
-                       status, tracks_new, tracks_updated
+                SELECT started_at, finished_at, region_id, source_id,
+                       status, tracks_new, errors_json
                 FROM pipeline_runs
-                ORDER BY started_at DESC
-                LIMIT 1
+                WHERE started_at = (SELECT MAX(started_at) FROM pipeline_runs)
+                ORDER BY region_id, source_id
                 """
             )
-            last_run_row = cur.fetchone()
-            last_run = dict(last_run_row) if last_run_row else None
+            run_rows = cur.fetchall()
+
+            if run_rows:
+                regions: list = []
+                sources_ok: list = []
+                sources_error: list = []
+                tracks_added = 0
+                finished_at_values: list = []
+
+                for row in run_rows:
+                    region = row["region_id"]
+                    if region not in regions:
+                        regions.append(region)
+
+                    if row["status"] in ("ok", "partial"):
+                        sources_ok.append(row["source_id"])
+                    else:
+                        sources_error.append(row["source_id"])
+
+                    tracks_added += row["tracks_new"] or 0
+
+                    if row["finished_at"]:
+                        finished_at_values.append(row["finished_at"])
+
+                last_run: Optional[dict] = {
+                    "started_at": run_rows[0]["started_at"],
+                    "finished_at": max(finished_at_values) if finished_at_values else None,
+                    "regions": regions,
+                    "sources_ok": sources_ok,
+                    "sources_error": sources_error,
+                    "tracks_added": tracks_added,
+                }
+            else:
+                last_run = None
 
             cur.execute("SELECT sources_json FROM tracks")
             tracks_by_source: dict = {}