feat(ui): add DataTable and Toaster, drop the legacy Table, fix overlay dialogs

DataTable replaces the 20-line Table scaffold entirely: columns, sorting,
filtering, pagination, selection, bulk actions, comparison layout, sticky
first column, custom HTML cells, and a remote source driven by a `request`
output rather than a function prop (props travel as HTML attributes, so a
function arrives as its own source text).

Toaster replaces the hand-rolled status div: tone icons, actions, hover
pause/resume and a progress bar.

Overlays audit -- Modal and Drawer declared aria-modal="true" but nothing
ever moved focus into the panel, so the @keydown handler on their root
never ran and closeOnEscape did nothing. Focus, focus restore, a Tab trap
and a body scroll lock now live in the reactive runtime, shared by both.

ContextMenu placed pointer menus by subtracting a guessed 340x420 from the
viewport, which pushed every menu that was not that size away from the
pointer; it now positions at the pointer and lets the anchored clamp pull
it back once it can be measured.

The reactive runtime size budget moves 150k -> 175k to cover anchored
overlays, dialog behaviour, the toaster and the DataTable client half.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

examples/component-showcase/showcase-manifest.json

@@ -2,7 +2,7 @@
   "generatedFrom": "packages/ui/component-reference.json",
   "componentCount": 108,
   "categoryCount": 11,
-  "totalDemoCount": 417,
+  "totalDemoCount": 421,
   "components": [
     {
       "name": "Accordion",
@@ -415,13 +415,22 @@
       "name": "DataTable",
       "mount": "DataTable",
       "slug": "data-table",
-      "category": "integrations",
-      "purpose": "Theme-aware, responsive data table component.",
-      "demoCount": 3,
-      "propCount": 7,
+      "category": "tables",
+      "purpose": "Sortable, filterable, paginated data table with row selection.",
+      "demoCount": 9,
+      "propCount": 29,
       "slots": ["default"],
-      "events": ["sort", "select", "change", "rowClick", "pageChange"],
-      "profiled": false
+      "events": [
+        "sort",
+        "search",
+        "pageChange",
+        "select",
+        "change",
+        "rowClick",
+        "action",
+        "request"
+      ],
+      "profiled": true
     },
     {
       "name": "DatePicker",
@@ -478,7 +487,7 @@
       "category": "overlays",
       "purpose": "Present responsive modal side or bottom content with focus management, backdrop behavior, slots, and close events.",
       "demoCount": 3,
-      "propCount": 19,
+      "propCount": 20,
       "slots": ["trigger", "header", "default", "footer"],
       "events": ["open", "close", "cancel"],
       "profiled": true
@@ -814,7 +823,7 @@
       "category": "overlays",
       "purpose": "Present an accessible modal dialog with focus management, confirmation, cancellation, slots, and responsive sizing.",
       "demoCount": 3,
-      "propCount": 28,
+      "propCount": 29,
       "slots": ["trigger", "header", "default", "footer"],
       "events": ["open", "close", "cancel", "confirm"],
       "profiled": true
@@ -1143,18 +1152,6 @@
       "events": ["input", "change", "focus", "blur"],
       "profiled": false
     },
-    {
-      "name": "Table",
-      "mount": "Table",
-      "slug": "table",
-      "category": "tables",
-      "purpose": "Theme-aware, responsive table component.",
-      "demoCount": 3,
-      "propCount": 7,
-      "slots": ["default"],
-      "events": ["sort", "select", "rowClick"],
-      "profiled": false
-    },
     {
       "name": "Tabs",
       "mount": "Tabs",
@@ -1239,6 +1236,18 @@
       "events": ["add", "dismiss", "clear", "action"],
       "profiled": false
     },
+    {
+      "name": "Toaster",
+      "mount": "Toaster",
+      "slug": "toaster",
+      "category": "core",
+      "purpose": "Reusable toaster component.",
+      "demoCount": 1,
+      "propCount": 15,
+      "slots": [],
+      "events": ["show", "dismiss", "action"],
+      "profiled": true
+    },
     {
       "name": "ToggleCount",
       "mount": "ToggleCount",