feat(courses): add type, search, and pricing filters to org landing page

- Add Types section to the Filter sidebar with all 4 course types
- Add full-text search input centered in the hero (title + description)
- Add Pricing section (Free / Paid) based on course cost
- Compact hero prop across all 10 themes to halve vertical padding
- Children snippet support in all hero themes for the search input
- All filters are URL-driven (?types=, ?search=, ?tags=, ?pricing=)
- Full-stack: validation schema, DB queries, service, API route, server load, UI

apps/dashboard/src/lib/utils/translations/en.json

@@ -1218,9 +1218,15 @@
     "subtitle": "Browse all published courses",
     "clear_filters": "Clear Filters",
     "filters": {
-      "title": "Filter by Tags",
-      "help": "Select one or more tags to filter courses",
-      "empty": "No tags available yet"
+      "title": "Filter",
+      "help": "Filter courses by type, tags, or search by name",
+      "tags_title": "Tags",
+      "types_title": "Types",
+      "pricing_title": "Pricing",
+      "pricing_free": "Free",
+      "pricing_paid": "Paid",
+      "empty": "No tags available yet",
+      "search_placeholder": "Search courses..."
     },
     "empty": {
       "title": "No courses found",