Rule dialog: only the zone fields the chain can use

Input and early have no outgoing interface, output no incoming one, so
the dialog hides those fields (they could only be refused) and a zone
left in a hidden field isn't sent.

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

CHANGELOG.md

@@ -115,6 +115,10 @@ All notable changes to Housecarl are documented here. The format follows
   ruleset, for entries made before this version too: the configuration
   before and after it is got back from the current one and rendered by
   this version.
+- The rule dialog shows only the zone fields its chain can use: no
+  "Going out on" for input and early, no "Coming in on" for output
+  (they could only be refused). A zone left in a field the chain hides
+  isn't sent.
 - History lists a changed setting by its own fields
   (`builtins.drop_invalid: false → true`), on the web page and in `hc
   history show`, instead of the whole `builtins` before and after.