Show AI tools only in edit mode; open existing summary without regenerating

- Hide AI tools panel when entry is not in edit mode
- Clicking AI button when a summary already exists opens it directly
  instead of triggering a new API call; Re-run still available in modal

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

src/lib/ae_elements/AE_AITools.svelte

@@ -157,9 +157,17 @@ function handle_save() {
     <!-- Trigger Button -->
     <button
         type="button"
-        onclick={generate_ai_result}
+        onclick={() => {
+            if (summary) {
+                tmp_summary = summary;
+                active_tab = 'result';
+                show_modal = true;
+            } else {
+                generate_ai_result();
+            }
+        }}
         class={buttonClass}
-        title="Generate AI summary/analysis">
+        title={summary ? 'View existing AI summary' : 'Generate AI summary/analysis'}>
         {#await ae_promises}
             <Loader class="mr-1 inline-block animate-spin" size="1.2em" />
             <span class="text-sm">Processing...</span>