feat(TRUEREF-0002): implement repository management service and REST API

Add RepositoryService with full CRUD, ID resolution helpers, input
validation, six SvelteKit API routes (GET/POST /api/v1/libs,
GET/PATCH/DELETE /api/v1/libs/:id, POST /api/v1/libs/:id/index), and
37 unit tests covering all service operations.

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

src/lib/server/utils/id-resolver.ts

@@ -0,0 +1,42 @@
+/**
+ * Repository ID generation utilities.
+ */
+
+/**
+ * Parse a GitHub URL into a canonical repository ID.
+ * Supports:
+ *   https://github.com/facebook/react
+ *   https://github.com/facebook/react.git
+ *   github.com/facebook/react
+ */
+export function resolveGitHubId(url: string): string {
+	const match = url.match(/github\.com\/([^/]+)\/([^/\s.]+)/);
+	if (!match) throw new Error('Invalid GitHub URL — expected github.com/owner/repo');
+	return `/${match[1]}/${match[2]}`;
+}
+
+/**
+ * Generate a local repository ID from an absolute path.
+ * Collision-resolves by appending -2, -3, etc.
+ */
+export function resolveLocalId(path: string, existingIds: string[]): string {
+	const base = slugify(path.split('/').at(-1) ?? 'repo');
+	let id = `/local/${base}`;
+	let counter = 2;
+	while (existingIds.includes(id)) {
+		id = `/local/${base}-${counter++}`;
+	}
+	return id;
+}
+
+/**
+ * Slugify a string to be safe for use in IDs.
+ */
+function slugify(str: string): string {
+	return str
+		.toLowerCase()
+		.replace(/[^a-z0-9-_]/g, '-')
+		.replace(/-+/g, '-')
+		.replace(/^-|-$/g, '')
+		|| 'repo';
+}