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

internal/handlers/target_edit.go

@@ -47,7 +47,7 @@ type targetEditView struct {
 //
 // This page is the one place the full destination URL and header
 // values are shown. It is reachable only through the
-// /source/{sourceID} route group, which supplies RequireAuth and
+// /hook/{sourceID} route group, which supplies RequireAuth and
 // NoCache, and only for a target of a webhook the session's user
 // owns; masking (delivery.TargetView) is unchanged everywhere else.
 func (h *Handlers) HandleTargetEdit() http.HandlerFunc {
@@ -163,7 +163,7 @@ func (h *Handlers) applyTargetEdit(
 	}
 
 	http.Redirect(
-		w, r, "/source/"+webhook.ID, http.StatusSeeOther,
+		w, r, "/hook/"+webhook.ID, http.StatusSeeOther,
 	)
 }