fix: metric samples timestamp + ssh-script port/user handling

- InsertMetricSample now includes ts=now() (TimescaleDB hypertable requires it)
- ssh-script: pass host and port separately (ssh uses -p flag, not host:port)
- ssh-script: use OIKOS_SSH_USER from config/env, default root
- Add -o LogLevel=ERROR to suppress SSH warnings polluting JSON output
- Use Output() (stdout only) instead of CombinedOutput()
- Set OIKOS_SSH_USER=root in scheduler docker-compose service

internal/db/sqlcgen/operations.sql.go

@@ -560,8 +560,8 @@ func (q *Queries) InsertFeedback(ctx context.Context, arg InsertFeedbackParams)
 }
 
 const insertMetricSample = `-- name: InsertMetricSample :exec
-INSERT INTO metric_samples (entity_id, metric, value, tags)
-VALUES ($1, $2, $3, $4)
+INSERT INTO metric_samples (entity_id, metric, value, tags, ts)
+VALUES ($1, $2, $3, $4, now())
 `
 
 type InsertMetricSampleParams struct {