feat(EMBEDDINGS-0001): enable local embedder by default and overhaul settings page

- Wire local embedding provider as the default on startup when no profile is configured
- Refactor embedding settings into dedicated service, DTOs, mappers and models
- Rebuild settings page with profile management UI and live test feedback
- Expose index summary (indexed versions + embedding count) on repo endpoints
- Harden indexing pipeline and context search with additional test coverage

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

src/routes/settings/+page.server.ts

@@ -0,0 +1,22 @@
+import type { PageServerLoad } from './$types';
+import { getClient } from '$lib/server/db/client.js';
+import { LocalEmbeddingProvider } from '$lib/server/embeddings/local.provider.js';
+import { EmbeddingSettingsDtoMapper } from '$lib/server/mappers/embedding-settings.dto.mapper.js';
+import { EmbeddingSettingsService } from '$lib/server/services/embedding-settings.service.js';
+
+export const load: PageServerLoad = async () => {
+	const service = new EmbeddingSettingsService(getClient());
+	const settings = EmbeddingSettingsDtoMapper.toDto(service.getSettings());
+
+	let localProviderAvailable = false;
+	try {
+		localProviderAvailable = await new LocalEmbeddingProvider().isAvailable();
+	} catch {
+		localProviderAvailable = false;
+	}
+
+	return {
+		settings,
+		localProviderAvailable
+	};
+};