fix(MULTIVERSION-0001): fix multi-version indexing — jobs never created or triggered for secondary versions

Two bugs prevented secondary versions from ever being indexed:

1. JobQueue.enqueue() and RepositoryService.createIndexingJob() deduplication
   only checked repository_id, so a queued default-branch job blocked all
   version-specific jobs for the same repo. Fix: include version_id in the
   WHERE clause so only exact (repository_id, version_id) pairs are deduped.

2. POST /api/v1/libs/:id/versions used repoService.createIndexingJob() which
   inserts a job record but never triggers queue processing. Fix: use
   queue.enqueue() (same fallback pattern as the libs endpoint) so setImmediate
   fires processNext() after the job is inserted.

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

src/lib/server/services/repository.service.ts

@@ -319,14 +319,17 @@ export class RepositoryService {
 	 * If a job is already running, returns the existing job.
 	 */
 	createIndexingJob(repositoryId: string, versionId?: string): IndexingJob {
-		// Check for running job
+		// Check for an existing queued/running job for this exact (repo, version) pair.
+		const resolvedVersionId = versionId ?? null;
 		const runningJob = this.db
 			.prepare(
 				`SELECT * FROM indexing_jobs
-           WHERE repository_id = ? AND status IN ('queued', 'running')
+           WHERE repository_id = ?
+             AND (version_id = ? OR (version_id IS NULL AND ? IS NULL))
+             AND status IN ('queued', 'running')
            ORDER BY created_at DESC LIMIT 1`
 			)
-			.get(repositoryId) as IndexingJobEntity | undefined;
+			.get(repositoryId, resolvedVersionId, resolvedVersionId) as IndexingJobEntity | undefined;
 
 		if (runningJob) return IndexingJobMapper.fromEntity(new IndexingJobEntity(runningJob));