fix(webui): build support bundle synchronously on download, bypass task queue

Support bundle is now built on-the-fly when the user clicks the button,
regardless of whether other tasks are running:

- GET /export/support.tar.gz builds the bundle synchronously and streams it
  directly to the client; the temp archive is removed after serving
- Remove POST /api/export/bundle and handleAPIExportBundle — the task-queue
  approach meant the bundle could only be downloaded after navigating away
  and back, and was blocked entirely while a long SAT test was running
- UI: single "Download Support Bundle" button; fetch+blob gives a loading
  state ("Building...") while the server collects logs, then triggers the
  browser download with the correct filename from Content-Disposition

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

audit/internal/webui/api.go

@@ -428,26 +428,6 @@ func (h *handler) handleAPIExportList(w http.ResponseWriter, r *http.Request) {
 	writeJSON(w, entries)
 }
 
-func (h *handler) handleAPIExportBundle(w http.ResponseWriter, r *http.Request) {
-	if globalQueue.hasActiveTarget("support-bundle") {
-		writeError(w, http.StatusConflict, "support bundle task is already pending or running")
-		return
-	}
-	t := &Task{
-		ID:        newJobID("support-bundle"),
-		Name:      "Support Bundle",
-		Target:    "support-bundle",
-		Status:    TaskPending,
-		CreatedAt: time.Now(),
-	}
-	globalQueue.enqueue(t)
-	writeJSON(w, map[string]string{
-		"status":  "queued",
-		"task_id": t.ID,
-		"job_id":  t.ID,
-		"url":     "/export/support.tar.gz",
-	})
-}
 
 func (h *handler) handleAPIExportUSBTargets(w http.ResponseWriter, _ *http.Request) {
 	if h.opts.App == nil {