feat(automation): expose group title and allow setting secondary text

Surface {{groupNow.*}} template variables (title, note, colour, times,
custom fields) in the automation template autocomplete so events inside a
group can reference their group. The runtime store already carries
groupNow, so substitution and filters worked already; this makes it
discoverable.

Extend the message-secondary action with an optional text field so an
automation can set the secondary message content, not just its source.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LZYPZVdZLWowU7DyzGkWyy

apps/client/src/features/app-settings/panel/automations-panel/template-input/templateInput.utils.ts

@@ -54,6 +54,16 @@ const eventStaticPropertiesNext = [
   '{{eventNext.delay}}',
 ];
 
+const groupStaticPropertiesNow = [
+  '{{groupNow.id}}',
+  '{{groupNow.title}}',
+  '{{groupNow.note}}',
+  '{{groupNow.colour}}',
+  '{{groupNow.timeStart}}',
+  '{{groupNow.timeEnd}}',
+  '{{groupNow.duration}}',
+];
+
 const staticAuxProperties = (index: 1 | 2 | 3) => [
   `{{auxtimer${index}.current}}`,
   `{{auxtimer${index}.duration}}`,
@@ -75,6 +85,8 @@ export function makeAutoCompleteList(customFields: CustomFields): string[] {
     ...Object.entries(customFields).map(([key]) => `{{eventNow.custom.${key}}}`),
     ...eventStaticPropertiesNext,
     ...Object.entries(customFields).map(([key]) => `{{eventNext.custom.${key}}}`),
+    ...groupStaticPropertiesNow,
+    ...Object.entries(customFields).map(([key]) => `{{groupNow.custom.${key}}}`),
     ...staticAuxProperties(1),
     ...staticAuxProperties(2),
     ...staticAuxProperties(3),