feat: two-phase indexation with direct thumbnail generation in indexer

Phase 1 (discovery): walkdir + filename-only metadata, zero archive I/O.
Books are visible immediately in the UI while Phase 2 runs in background.

Phase 2 (analysis): open each archive once via analyze_book() to extract
page_count and first page bytes, then generate WebP thumbnail directly in
the indexer — removing the HTTP roundtrip to the API checkup endpoint.

- Add parse_metadata_fast() (infallible, no archive I/O)
- Add analyze_book() returning (page_count, first_page_bytes) in one pass
- Add looks_like_image() magic bytes check for unrar p stdout validation
- Add lsar fallback in list_cbr_images() for UTF-16BE encoded filenames
- Add directory_mtimes table to skip unchanged dirs on incremental scans
- Add analyzer.rs: generate_thumbnail, analyze_library_books, regenerate_thumbnails
- Remove run_checkup() from API; indexer handles thumbnail jobs directly
- Remove api_base_url/api_bootstrap_token from IndexerConfig and AppState
- Add unar + poppler-utils to indexer Dockerfile
- Fix smoke.sh: wait for job completion, check thumbnail_url field

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

apps/indexer/src/meili.rs

@@ -100,7 +100,7 @@ pub async fn sync_meili(pool: &PgPool, meili_url: &str, meili_master_key: &str)
     const MEILI_BATCH_SIZE: usize = 1000;
     for (i, chunk) in docs.chunks(MEILI_BATCH_SIZE).enumerate() {
         let batch_num = i + 1;
-        info!("[MEILI] Sending batch {}/{} ({} docs)", batch_num, (doc_count + MEILI_BATCH_SIZE - 1) / MEILI_BATCH_SIZE, chunk.len());
+        info!("[MEILI] Sending batch {}/{} ({} docs)", batch_num, doc_count.div_ceil(MEILI_BATCH_SIZE), chunk.len());
         
         let response = client
             .post(format!("{base}/indexes/books/documents"))