fix(launcher): hidden sessions collapse space, sort by datetime, rename internal-file flag

- menu_session_list: move class:hidden to <li> so fixed-height rows fully collapse
- launcher/+layout.svelte: sort sessions by start_datetime (ascending) instead of name
- Rename hide_content__draft_files → show_content__internal_files (default false);
  remove redundant show_content__draft_files; rename prop hide_draft →
  show_internal_purpose_files in launcher_file_cont; update all 7 call sites and
  the menu_launcher_controls toggle. Now hides admin/draft/outline purpose files
  by default with consistent naming across the flag, prop, and toggle.

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

src/lib/stores/ae_events_stores__launcher_defaults.ts

@@ -26,13 +26,12 @@ export interface LauncherLocState {
     hide__ws_form: boolean;
     hide__ws_messages: boolean;
     hide__ws_commands: boolean;
-    hide_content__draft_files: boolean;
     show_content__disabled_files: boolean;
     show_content__hidden_files: boolean;
     show_content__hidden_presentations: boolean;
     show_content__hidden_presenters: boolean;
     show_content__hidden_sessions: boolean;
-    show_content__draft_files: boolean;
+    show_content__internal_files: boolean;
     show_content__session_code: boolean;
     show_content__presentation_code: boolean;
     show_content__presenter_code: boolean;
@@ -134,14 +133,12 @@ export const launcher_loc_defaults: LauncherLocState = {
     hide__ws_messages: true,
     hide__ws_commands: true,
 
-    hide_content__draft_files: true,
-
     show_content__disabled_files: false,
     show_content__hidden_files: false,
     show_content__hidden_presentations: false,
     show_content__hidden_presenters: false,
     show_content__hidden_sessions: false,
-    show_content__draft_files: false,
+    show_content__internal_files: false,
 
     // These should be renamed to match the pres_mgmt section. Use "hide" instead of "show".
     show_content__session_code: true,