refactor(catalog-react): migrate InspectEntityDialog from MUI to BUI

Replace Material UI components with Backstage UI (BUI) equivalents
across the InspectEntityDialog and all its tab pages (Overview,
Ancestry, Colocated, JSON, YAML).

- Dialog shell uses BUI Dialog, DialogHeader, DialogBody, Tabs
- Horizontal tab bar replaces vertical MUI tabs
- Card sections use BUI Card, CardHeader, CardBody
- Key-value pairs rendered as semantic dl/dt/dd elements
- Copy buttons use BUI ButtonIcon with remixicon icons
- Help links use BUI ButtonLink
- Alerts use BUI Alert
- Tags use BUI TagGroup/Tag
- Accessible live region for copy confirmation
- Proper heading hierarchy (h2 for tab pages, h3 for cards, h4 for sections)
- Added OverviewPage tests for identity rendering, link detection, and tags

Signed-off-by: Johan Persson <johanopersson@gmail.com>

yarn.lock

@@ -5342,6 +5342,7 @@ __metadata:
     "@material-ui/icons": "npm:^4.9.1"
     "@material-ui/lab": "npm:4.0.0-alpha.61"
     "@react-hookz/web": "npm:^24.0.0"
+    "@remixicon/react": "npm:^4.6.0"
     "@testing-library/dom": "npm:^10.0.0"
     "@testing-library/jest-dom": "npm:^6.0.0"
     "@testing-library/react": "npm:^16.0.0"