Store and show an event's query string, and pass it on to an HTTP target when set (closes #312)

The receiver dropped the query string of every request it received, so a sender's URL parameters were silently lost. Each event now keeps it, as sent, in a new `raw_query` column of the per-webhook `events` table; a resubmitted copy carries its original's. The event log and the event's page show it in the shared request block, the event log leaving out one over 32 KiB with a link, as for headers. The archive and log targets carry it. HTTP targets gain "Pass the query string on to this target", off by default: on, deliveries, replays and resubmits append it to the target URL, joined with `&` to one already there. The access log still hides it.

Model: opus-5-5

templates/event_request.html

@@ -1,15 +1,23 @@
 {{define "event_request"}}
-<!-- The entrypoint an event arrived at and its request headers, as
-     handlers.EventLogView carries them: the same in the event log and
-     the event's own page. The entrypoint's URL is never shown. A
-     resubmitted copy, even a copy of a copy, did not arrive at an
-     entrypoint; the request it copies did. -->
+<!-- The entrypoint an event arrived at, its query string and its
+     request headers, as handlers.EventLogView carries them: the same in
+     the event log and the event's own page. The entrypoint's URL is
+     never shown. A resubmitted copy, even a copy of a copy, did not
+     arrive at an entrypoint; the request it copies did. -->
 <div class="space-y-2 text-xs">
     {{if .ResubmittedFrom}}
     <p class="text-gray-500">The request it copies arrived at <span class="text-gray-900 wrap-anywhere">{{.Entrypoint}}</span></p>
     {{else}}
     <p class="text-gray-500">Arrived at <span class="text-gray-900 wrap-anywhere">{{.Entrypoint}}</span></p>
     {{end}}
+    {{if .RawQueryCut}}
+    <p class="text-gray-500">The query string is larger than the event log shows. <a href="{{.Body.EventURL}}" class="btn-small">Show the query string</a></p>
+    {{else if .RawQuery}}
+    <p class="text-gray-500">Query string</p>
+    <pre class="rounded-md border border-gray-200 bg-white p-2 text-xs text-gray-700 overflow-x-auto whitespace-pre-wrap break-all">{{.RawQuery}}</pre>
+    {{else}}
+    <p class="text-gray-500">No query string.</p>
+    {{end}}
     {{if .HeadersCut}}
     <p class="text-gray-500">The request headers are larger than the event log shows. <a href="{{.Body.EventURL}}" class="btn-small">Show the request headers</a></p>
     {{else if .Headers}}