Apps Phase 1: docs, examples, app-only tool filtering (#3593)

* Apps Phase 1: docs, examples, app-only tool filtering, Rx() migration

* Clarify architecture page is Prefab-specific

* Fix component reference inaccuracies and DataTable search prop

- Charts import: clarify they must come from prefab_ui.components.charts
- DataTable: searchable→search (the actual prop name), remove nonexistent
  table-level sortable prop
- Select: remove nonexistent options prop, show SelectOption children
- Tabs: default_value→value
- Fix search=True in inventory, patterns, datatable examples

* Consistent Rx usage across all examples, fix imports

* Address review: fix chart imports, Select import, docstring --stdio claims

examples/apps/datatable_server.py

@@ -57,7 +57,7 @@ def team_directory(department: str | None = None) -> Column:
                 DataTableColumn(key="location", header="Location", sortable=True),
             ],
             rows=rows,
-            searchable=True,
+            search=True,
             paginated=True,
         )
     return view