Fix start date in workload overview report to midnight

This is the expected behavior: when no start date is given, it should default to
today (the whole day), and not exactly now, so that day increments do not start
in the mid of the day, yielding misleading results.

site-lisp/db-org.el

@@ -575,7 +575,7 @@ PARAMS is a property list of the following parameters:
          (org-ql-match (or (plist-get params :org-ql-match)
                            '(todo)))
          (current (or start-date
-                      (org-read-date nil nil ".")))
+                      (org-read-date nil nil ". 00:00")))
          (date-range nil))
 
     ;; Check input