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 follow every link and submit every form the
templates render to a moved page, through the production router, with
the link, form action and token taken from the rendered page.

Model: opus-5-5

internal/handlers/event_body_test.go

@@ -64,8 +64,8 @@ func fetchEventBody(
 	req := httptest.NewRequestWithContext(
 		context.Background(),
 		http.MethodGet,
-		"/source/"+url.PathEscape(sourceID)+
-			"/logs/"+url.PathEscape(eventID)+"/body",
+		"/hook/"+url.PathEscape(sourceID)+
+			"/events/"+url.PathEscape(eventID)+"/body",
 		nil,
 	)
 
@@ -490,7 +490,7 @@ func TestHandleSourceLogs_TruncationMarkerLinksToDownload(
 	page := renderSourceLogsPage(t, h, sess, big.ID)
 	assert.Contains(
 		t, page,
-		"/source/"+big.ID+"/logs/"+bigEvt.ID+"/body",
+		"/hook/"+big.ID+"/events/"+bigEvt.ID+"/body",
 	)
 
 	small := seedWebhook(t, db)
@@ -501,6 +501,6 @@ func TestHandleSourceLogs_TruncationMarkerLinksToDownload(
 	page = renderSourceLogsPage(t, h, sess, small.ID)
 	assert.NotContains(
 		t, page,
-		"/source/"+small.ID+"/logs/"+smallEvt.ID+"/body",
+		"/hook/"+small.ID+"/events/"+smallEvt.ID+"/body",
 	)
 }