fix(mcp): get_anomaly keeps the events nearest the occurrence and says how many it left out (#5861)

Each source in an anomaly's `around` was cut to its oldest 40 with
nothing in the reply to say so; on a busy host the events nearest the
occurrence were the ones dropped. Each source now keeps the 40 nearest
the occurrence's start, and `around_left_out` counts the rest. Sources
return everything their bounded query read (Docker and the host agent
no longer cut at 40 and 20 themselves), so the count is honest.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

plugins/host_agent/mcp_tools.py

@@ -303,7 +303,7 @@ async def mcp_events(db, host_id: str, host_name: str, since, until) -> list[dic
     jobs = (await db.execute(select(HostMaintenanceJob).where(
         HostMaintenanceJob.host_id == host_id, HostMaintenanceJob.created_at <= until,
         (HostMaintenanceJob.finished_at.is_(None)) | (HostMaintenanceJob.finished_at >= since))
-        .order_by(HostMaintenanceJob.created_at).limit(20))).scalars()
+        .order_by(HostMaintenanceJob.created_at).limit(200))).scalars()
     for job in jobs:
         out.append(event(job.created_at, "maintenance", f"Maintenance: {maintenance.summary(job)}",
                          until=job.finished_at, ids={"job_id": job.id}))
@@ -311,7 +311,7 @@ async def mcp_events(db, host_id: str, host_name: str, since, until) -> list[dic
     rows = (await db.execute(select(HostDowntime).where(
         HostDowntime.host_id == host_id, HostDowntime.started_at <= until,
         (HostDowntime.ended_at.is_(None)) | (HostDowntime.ended_at >= since))
-        .order_by(HostDowntime.started_at).limit(20))).scalars()
+        .order_by(HostDowntime.started_at).limit(200))).scalars()
     for row in rows:
         seen = downtime.describe(row, now)
         out.append(event(row.started_at, "downtime",