clock: ensure launch is listening correctly

In the wild, ships that were live pre-OS1 still had launch subscriptions
open to the clock on the /tile path, instead of the currently-used
/clocktile path. Additionally, launch state for the clock tile seemed
incomplete.

Here, we simply re-%add the clock to launch.

Note that launch currently does not clean up old subscriptions on
path change. For the pre-OS1 case, the old path is no longer in use,
rendering the subscription harmless. For cases where the correct
subscription was already in place, it'll print a %watch-wire-not-unique,
but doesn't do any harm besides that.

pkg/arvo/app/clock.hoon

@@ -35,13 +35,21 @@
   ==
 ::  bootstrapping to get %goad started OTA
 ::
-++  on-save   !>(%2)
+++  on-save   !>(%3)
 ++  on-load
   |=  old-state=vase
-  =/  old  !<(?(~ %1 %2) old-state)
+  ^-  (quip card _this)
+  =/  old  !<(?(~ %1 %2 %3) old-state)
   =^  cards  this
-    ?:  ?=(%2 old)
+    ?:  ?=(%3 old)
       `this
+    ?:  ?=(%2 old)
+      ::  ensure launch is set up to listen to us correctly
+      ::
+      =/  launcha
+        [%launch-action !>([%add %clock /clocktile '/~clock/js/tile.js'])]
+      :_  this
+      [%pass /clock %agent [our.bowl %launch] %poke launcha]~
     :_  this  :_  ~
     [%pass /behn %arvo %b %wait +(now.bowl)]
   ::