Fix typo in mermaid diagram comment

Changed "notifation" to "notification" in the interactive phase sequence
diagram.

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Co-Authored-By: Claude <[email protected]>

Author: jonathanhefner

specification/draft/apps.mdx

@@ -706,7 +706,7 @@ sequenceDiagram
    H -->> H: Process message and follow up
  else Notify
      UI ->> H: notifications/message
-     H ->> H: Process notifation and store in context
+     H ->> H: Process notification and store in context
  else Resource read
      UI ->> H: resources/read
      H ->> S: resources/read