Move webhook pages to /hook/ID and inbound URLs to /h/UUID (closes #367)

The webhook page and everything under it move from /source/ID to
/hook/ID, the list and new-webhook form to /hooks and /hooks/new, and
the event log from .../logs to /hook/ID/events, body download
included. Entrypoint URLs move from /webhook/UUID to /h/UUID, and the
webhook page shows only that form. The old paths are gone.

Links, redirects, form actions, tests, comments and the README follow.
Both links to the event log page, and its title and heading, now read
"Full Event Log". Go identifiers and template file names are
unchanged. Route tests reach every moved page and form through the
production router, taking each URL and token from the rendered page.

Model: opus-5-5

templates/navbar.html

@@ -16,7 +16,7 @@
         <!-- Desktop navigation -->
         <div class="hidden md:flex items-center gap-4">
             {{if .User}}
-            <a href="/sources" class="btn-text">Webhooks</a>
+            <a href="/hooks" class="btn-text">Webhooks</a>
             <a href="/user/{{.User.Username}}" class="btn-text">
                 <svg class="w-5 h-5 mr-1" fill="currentColor" viewBox="0 0 16 16">
                     <path d="M11 6a3 3 0 1 1-6 0 3 3 0 0 1 6 0z"/>
@@ -38,7 +38,7 @@
     <div x-show="open" x-cloak x-transition class="md:hidden mt-4 pt-4 border-t border-gray-200">
         <div class="flex flex-col gap-2">
             {{if .User}}
-            <a href="/sources" class="btn-text w-full text-left">Webhooks</a>
+            <a href="/hooks" class="btn-text w-full text-left">Webhooks</a>
             <a href="/user/{{.User.Username}}" class="btn-text w-full text-left">Profile</a>
             <form method="POST" action="/pages/logout">
                 <input type="hidden" name="csrf_token" value="{{.CSRFToken}}">