fix: structured approvals + ToolCallGroup reactivity

- Replace text-based regex parsing in InlineApproval with structured
  pendingApprovals extracted from request_execution tool results. The tool
  result text is deterministic (not LLM-generated), making UUID extraction
  reliable regardless of how the LLM rephrases the response.

- Fix ToolCallGroup  reactivity: wasActive = active captured initial
  value. Now uses (active) so  re-runs on prop changes.

- Extract approvals in both live streaming (done event) and history loading
  for consistent behavior on resumed sessions.

web/src/lib/components/ToolCallGroup.svelte

@@ -10,7 +10,7 @@
   let { tools, active = false }: { tools: ToolCallResult[]; active?: boolean } = $props()
 
   let open = $state(false)
-  let wasActive = active
+  let wasActive = $state(active)
 
   $effect(() => {
     if (active && !wasActive) {