feat(worker): ручной пересчёт метрик через очередь, диагностика шагов и heartbeat

POST /metrics/refresh ставит задачу в sync_job (source=METRICS_JOB) и отвечает 202, пересчёт делает worker; GET /metrics/status отдаёт refreshing и consistent. metric_refresh_log хранит failed_step и step_timings. Источники с needs="tinvest_token" не попадают в расписание без токена, tinvest/moex добавлены в default_schedule. Воркер трогает heartbeat-файл для healthcheck.

backend/src/fintracker/models/__init__.py

@@ -72,6 +72,7 @@ from fintracker.models.reports import (
     ReportParseStatus,
 )
 from fintracker.models.sync import (
+    METRICS_JOB,
     JobStatus,
     RunStatus,
     SourceCredential,
@@ -101,6 +102,7 @@ from fintracker.models.zenmoney import (
 
 __all__ = [
     "EXTERNAL_FLOW_KINDS",
+    "METRICS_JOB",
     "POSITION_KINDS",
     "Account",
     "AccountKind",

backend/src/fintracker/models/metrics.py

@@ -135,6 +135,11 @@ class MetricRefreshLog(Base):
     trigger: Mapped[str] = mapped_column(String(32))
     """sync:<source> | manual | cli"""
     error: Mapped[str | None] = mapped_column(Text)
+    failed_step: Mapped[str | None] = mapped_column(String(64))
+    """Name of the step that raised. Steps before it committed and the ones after it did not
+    run, so the metric tables then come from two different runs."""
+    step_timings: Mapped[dict[str, Any] | None]
+    """Seconds per step that completed, in run order."""
 
 
 class MetricPortfolioValueDaily(Base):

backend/src/fintracker/models/sync.py

@@ -19,6 +19,11 @@ class RunStatus(enum.StrEnum):
     error = "error"
 
 
+METRICS_JOB = "metrics"
+"""`sync_job.source` of a queued metrics rebuild. Not a registered source: the worker
+routes it to `refresh_all` instead of `run_source`, and `POST /sync/{source}` answers 404."""
+
+
 class JobStatus(enum.StrEnum):
     queued = "queued"
     running = "running"
@@ -55,7 +60,8 @@ class SyncRun(Base):
 
 
 class SyncJob(Base):
-    """Manual trigger queue: API inserts, worker picks up (plan §2.4)."""
+    """Manual trigger queue: API inserts, worker picks up (plan §2.4). Also carries the metrics
+    rebuild requested by `POST /metrics/refresh`, as `source == METRICS_JOB`."""
 
     __tablename__ = "sync_job"