Move Conpherence to "Z" monogram instead of "E"

Summary:
Ref T7439. Fixes T7438. This is only used in email right now.

Remain backward compatible.

Test Plan:
  - Sent a message, saw a "Z" reply address.
  - Checked the PHIDType.
  - Grepped for `"E"` and `'E'`.

Reviewers: btrahan

Reviewed By: btrahan

Subscribers: epriestley

Maniphest Tasks: T7439, T7438

Differential Revision: https://secure.phabricator.com/D11956

src/applications/conpherence/mail/ConpherenceReplyHandler.php

@@ -20,11 +20,11 @@ final class ConpherenceReplyHandler extends PhabricatorMailReplyHandler {
 
   public function getPrivateReplyHandlerEmailAddress(
     PhabricatorObjectHandle $handle) {
-    return $this->getDefaultPrivateReplyHandlerEmailAddress($handle, 'E');
+    return $this->getDefaultPrivateReplyHandlerEmailAddress($handle, 'Z');
   }
 
   public function getPublicReplyHandlerEmailAddress() {
-    return $this->getDefaultPublicReplyHandlerEmailAddress('E');
+    return $this->getDefaultPublicReplyHandlerEmailAddress('Z');
   }
 
   public function getReplyHandlerInstructions() {

src/applications/conpherence/mail/ConpherenceThreadMailReceiver.php

@@ -9,11 +9,13 @@ final class ConpherenceThreadMailReceiver
   }
 
   protected function getObjectPattern() {
-    return 'E[1-9]\d*';
+    // TODO: Only recognize "Z" once we get closer to shipping Calendar.
+    return '[EZ][1-9]\d*';
   }
 
   protected function loadObject($pattern, PhabricatorUser $viewer) {
-    $id = (int)trim($pattern, 'E');
+    // TODO: Only recognize "Z" once we get closer to shipping Calendar.
+    $id = (int)trim($pattern, 'EZ');
 
     return id(new ConpherenceThreadQuery())
       ->setViewer($viewer)