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/repository.service.ts

@@ -39,6 +39,11 @@ export interface RepositoryStats {
 	lastIndexedAt: Date | null;
 }
 
+export interface RepositoryIndexSummary {
+	embeddingCount: number;
+	indexedVersions: string[];
+}
+
 export class RepositoryService {
 	constructor(private readonly db: Database.Database) {}
 
@@ -266,6 +271,49 @@ export class RepositoryService {
 		return rows.map((r) => r.tag);
 	}
 
+	getIndexSummary(repositoryId: string): RepositoryIndexSummary {
+		const repository = this.get(repositoryId);
+		if (!repository) throw new NotFoundError(`Repository ${repositoryId} not found`);
+
+		const embeddingRow = this.db
+			.prepare(
+				`SELECT COUNT(*) AS count
+				 FROM snippet_embeddings se
+				 INNER JOIN snippets s ON s.id = se.snippet_id
+				 WHERE s.repository_id = ?`
+			)
+			.get(repositoryId) as { count: number };
+
+		const versionRows = this.db
+			.prepare(
+				`SELECT tag FROM repository_versions
+				 WHERE repository_id = ? AND state = 'indexed'
+				 ORDER BY created_at DESC`
+			)
+			.all(repositoryId) as { tag: string }[];
+
+		const hasDefaultBranchIndex = Boolean(
+			this.db
+				.prepare(
+					`SELECT 1 AS found
+					 FROM documents
+					 WHERE repository_id = ? AND version_id IS NULL
+					 LIMIT 1`
+				)
+				.get(repositoryId)
+		);
+
+		const indexedVersions = [
+			...(hasDefaultBranchIndex ? [repository.branch ?? 'default branch'] : []),
+			...versionRows.map((row) => row.tag)
+		];
+
+		return {
+			embeddingCount: embeddingRow.count,
+			indexedVersions: Array.from(new Set(indexedVersions))
+		};
+	}
+
 	/**
 	 * Create an indexing job for a repository.
 	 * If a job is already running, returns the existing job.