issue 1858: handle, unhandle and remind an item, each with its own line (1858.2)

ADR 0517 §1, §2, §4, §5: an item is a task, a promise or the mail itself; each act and its action line are
kept in one transaction, a refused or failed act writes none, an undo lasts until the day ends and a
reminder shows the item again the next day (Europe/Brussels). The seat's serves list in mesh-mail's
manifest names the new verbs.

modules/mesh-mail-reader/module.json

@@ -6,7 +6,7 @@
     {
       "name": "mail-reading",
       "scope": "mesh",
-      "serves": ["entries", "groups", "correct", "lessons", "undo", "status"]
+      "serves": ["entries", "groups", "correct", "lessons", "undo", "status", "handle", "unhandle", "remind"]
     }
   ],
   "consumes": [
@@ -48,6 +48,9 @@
     "mail-reading.lessons",
     "mail-reading.undo",
     "mail-reading.status",
+    "mail-reading.handle",
+    "mail-reading.unhandle",
+    "mail-reading.remind",
     "mail_reader_health"
   ],
   "runtime-health": {