refactor: move lib-root files to lib/shared/ and finalize domain structure

- Move api.server.ts, errors.ts, types.ts, utils.ts, relativeTime.ts to lib/shared/
- Move person relationship components to lib/person/relationship/
- Move Stammbaum components to lib/person/genealogy/
- Move HelpPopover to lib/shared/primitives/
- Update all import paths across routes, specs, and lib files
- Update vi.mock() paths in server-project test files
- Remove now-empty legacy directories (components/, hooks/, server/, etc.)
- Update vite.config.ts coverage include paths for new structure
- Update frontend/CLAUDE.md to reflect domain-based lib/ layout

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/vite.config.ts

@@ -48,7 +48,7 @@ export default defineConfig({
 			reporter: ['text', 'lcov'],
 			// Measure utility and server-side logic only — Svelte components
 			// run in the browser project and are excluded here intentionally.
-			include: ['src/lib/utils/**', 'src/lib/server/**'],
+			include: ['src/lib/shared/**', 'src/lib/document/**', 'src/lib/person/**'],
 			thresholds: {
 				branches: 80
 			}