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/lib/server/services/embedding-settings.service.ts

@@ -0,0 +1,131 @@
+import type Database from 'better-sqlite3';
+import type { EmbeddingSettingsUpdateDto } from '$lib/dtos/embedding-settings.js';
+import { createProviderFromProfile, getDefaultLocalProfile } from '$lib/server/embeddings/registry.js';
+import { EmbeddingProfileMapper } from '$lib/server/mappers/embedding-profile.mapper.js';
+import { EmbeddingProfile, EmbeddingProfileEntity } from '$lib/server/models/embedding-profile.js';
+import { EmbeddingSettings } from '$lib/server/models/embedding-settings.js';
+import { InvalidInputError } from '$lib/server/utils/validation.js';
+
+export class EmbeddingSettingsService {
+	constructor(private readonly db: Database.Database) {}
+
+	getSettings(): EmbeddingSettings {
+		const profiles = this.loadProfiles();
+		const activeProfile = profiles.find((profile) => profile.isDefault && profile.enabled) ?? null;
+
+		return new EmbeddingSettings({ profiles, activeProfile });
+	}
+
+	async updateSettings(input: EmbeddingSettingsUpdateDto): Promise<EmbeddingSettings> {
+		const now = Math.floor(Date.now() / 1000);
+
+		this.db.prepare('UPDATE embedding_profiles SET is_default = 0, updated_at = ?').run(now);
+
+		if (input.activeProfileId === null) {
+			return this.getSettings();
+		}
+
+		const profile =
+			input.activeProfileId === 'local-default'
+				? this.buildDefaultLocalProfile(now)
+				: this.buildCustomProfile(input, now);
+
+		const available = await createProviderFromProfile(profile).isAvailable();
+		if (!available) {
+			throw new InvalidInputError(
+				`Could not connect to the "${profile.providerKind}" provider. Check your configuration.`
+			);
+		}
+
+		this.persistProfile(profile);
+		return this.getSettings();
+	}
+
+	private loadProfiles(): EmbeddingProfile[] {
+		return this.db
+			.prepare('SELECT * FROM embedding_profiles ORDER BY is_default DESC, created_at ASC')
+			.all()
+			.map((row) => EmbeddingProfileMapper.fromEntity(new EmbeddingProfileEntity(row as never)));
+	}
+
+	private buildDefaultLocalProfile(now: number): EmbeddingProfile {
+		const defaultLocal = getDefaultLocalProfile();
+
+		return new EmbeddingProfile({
+			id: defaultLocal.id,
+			providerKind: defaultLocal.providerKind,
+			title: defaultLocal.title,
+			enabled: true,
+			isDefault: true,
+			model: defaultLocal.model,
+			dimensions: defaultLocal.dimensions,
+			config: {},
+			createdAt: this.getCreatedAt(defaultLocal.id, now),
+			updatedAt: now
+		});
+	}
+
+	private buildCustomProfile(input: EmbeddingSettingsUpdateDto, now: number): EmbeddingProfile {
+		const candidate = input.profile;
+		if (!candidate) {
+			throw new InvalidInputError('profile is required for custom embedding providers');
+		}
+		if (candidate.id !== input.activeProfileId) {
+			throw new InvalidInputError('activeProfileId must match profile.id');
+		}
+		if (!candidate.title || !candidate.model) {
+			throw new InvalidInputError('profile title and model are required');
+		}
+
+		return new EmbeddingProfile({
+			id: candidate.id,
+			providerKind: candidate.providerKind,
+			title: candidate.title,
+			enabled: true,
+			isDefault: true,
+			model: candidate.model,
+			dimensions: candidate.dimensions,
+			config: candidate.config,
+			createdAt: this.getCreatedAt(candidate.id, now),
+			updatedAt: now
+		});
+	}
+
+	private getCreatedAt(id: string, fallback: number): number {
+		return (
+			this.db
+				.prepare<[string], { created_at: number }>('SELECT created_at FROM embedding_profiles WHERE id = ?')
+				.get(id)?.created_at ?? fallback
+		);
+	}
+
+	private persistProfile(profile: EmbeddingProfile): void {
+		this.db
+			.prepare(
+				`INSERT INTO embedding_profiles
+				   (id, provider_kind, title, enabled, is_default, model, dimensions, config, created_at, updated_at)
+				 VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
+				 ON CONFLICT(id) DO UPDATE SET
+				   provider_kind = excluded.provider_kind,
+				   title = excluded.title,
+				   enabled = excluded.enabled,
+				   is_default = excluded.is_default,
+				   model = excluded.model,
+				   dimensions = excluded.dimensions,
+				   config = excluded.config,
+				   updated_at = excluded.updated_at`
+			)
+			.run(
+				profile.id,
+				profile.providerKind,
+				profile.title,
+				profile.enabled ? 1 : 0,
+				profile.isDefault ? 1 : 0,
+				profile.model,
+				profile.dimensions,
+				JSON.stringify(profile.config),
+				profile.createdAt,
+				profile.updatedAt
+			);
+	}
+}