Remove _random ID references and fix hosted file download ID

- Fix download button to use hosted_file_id instead of id (which resolved
  to event_file_id via _process_generic_props, hitting the wrong endpoint)
- Fix Dexie file table query in event_file_obj_tbl_wrapper to use _id
  fields (the indexed ones) instead of _id_random variants
- Remove _random fields from properties_to_save in event, event_session
- Drop _id_random fallbacks from launcher device ID resolution and
  background sync heartbeat
- Clean up dead comments and old FA anchor in post edit component
- Update TODO__Agents.md: BGH section removed, CMSC/Axonius shows added,
  download button fix marked complete

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

src/routes/events/[event_id]/(pres_mgmt)/reports/+page.svelte

@@ -77,10 +77,10 @@ let lq__event_obj = $derived(
 );
 
 // It is important that these not be set to a value! It messes with the Dexie LiveQuery.
-// let event_file_id_random_li: Array<string> = $state();
-// let event_session_id_random_li: Array<string> = $state();
-// let event_presentation_id_random_li: Array<string>;
-// let event_presenter_id_random_li: Array<string> = $state();
+// let event_file_id_li: Array<string> = $state();
+// let event_session_id_li: Array<string> = $state();
+// let event_presentation_id_li: Array<string>;
+// let event_presenter_id_li: Array<string> = $state();
 
 // let load_obj_li_results: Promise<any>|key_val;
 // let search_submit_results: Promise<any>|key_val;
@@ -142,9 +142,11 @@ $effect(() => {
             </span>
             <!-- Reports for: -->
             {#if $lq__event_obj?.cfg_json?.short_name}
+                <!-- eslint-disable-next-line svelte/no-at-html-tags -->
                 {@html $lq__event_obj?.cfg_json.short_name ??
                     ae_snip.html__not_set}
             {:else}
+                <!-- eslint-disable-next-line svelte/no-at-html-tags -->
                 {@html $lq__event_obj?.name ?? ae_snip.html__not_set}
             {/if}
         </h2>