ci: revert dashboard examples from smoke tests — Octave @-folder limit

Octave 8.4.0 still requires abstract methods to be in @-folders.
DashboardWidget.m uses methods(Abstract) in a plain .m file which
causes "external methods are only allowed in @-folders" parse error.

Move all dashboard/widget examples back to the skip list with the
correct reason documented.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: HanSur94

.github/workflows/examples.yml

@@ -87,27 +87,6 @@ jobs:
             example_sensor_dashboard
             # Heavy
             example_dynamic_thresholds_100M
-            # DashboardEngine (classdef — Octave 8+ should handle these)
-            example_dashboard_engine
-            example_dashboard_all_widgets
-            example_dashboard_groups
-            example_dashboard_info
-            example_dashboard_advanced
-            example_widget_fastsense
-            example_widget_number
-            example_widget_status
-            example_widget_text
-            example_widget_gauge
-            example_widget_table
-            example_widget_rawaxes
-            example_widget_timeline
-            example_widget_group
-            example_widget_barchart
-            example_widget_heatmap
-            example_widget_histogram
-            example_widget_scatter
-            example_widget_image
-            example_widget_multistatus
             # -----------------------------------------------------------------
             # Skipped — Octave-incompatible (MATLAB-only features):
             #   example_themes                 — segfault in Octave figure cleanup
@@ -119,6 +98,10 @@ jobs:
             #   example_sensor_detail_*        — 'disableDefaultInteractivity' / datetime
             #   example_sensor_todisk          — MATLAB-only API
             #   example_stress_test            — interactive / long-running
+            # Skipped — DashboardWidget uses abstract methods, Octave requires @-folders:
+            #   example_dashboard_engine       example_dashboard_all_widgets
+            #   example_dashboard_groups       example_dashboard_info
+            #   example_dashboard_advanced     example_widget_*
             # Skipped — requires interaction / runs indefinitely:
             #   demo_all                       — input() call
             #   example_dashboard_live         — live timer