feat(jobs): introduce extracting_pages status and update job progress handling

- Added a new job status 'extracting_pages' to represent the first sub-phase of thumbnail generation.
- Updated the database schema to include a timestamp for when thumbnail generation starts.
- Enhanced job progress components to handle the new status, including UI updates for displaying progress and status labels.
- Refactored job-related logic to accommodate the two-phase process: extracting pages and generating thumbnails.
- Adjusted SQL queries and job detail responses to include the new fields and statuses.

This change improves the clarity of job processing states and enhances user feedback during the thumbnail generation process.

apps/api/src/index_jobs.rs

@@ -65,6 +65,8 @@ pub struct IndexJobDetailResponse {
     pub finished_at: Option<DateTime<Utc>>,
     #[schema(value_type = Option<String>)]
     pub phase2_started_at: Option<DateTime<Utc>>,
+    #[schema(value_type = Option<String>)]
+    pub generating_thumbnails_started_at: Option<DateTime<Utc>>,
     pub stats_json: Option<serde_json::Value>,
     pub error_opt: Option<String>,
     #[schema(value_type = String)]
@@ -324,6 +326,7 @@ fn map_row_detail(row: sqlx::postgres::PgRow) -> IndexJobDetailResponse {
         started_at: row.get("started_at"),
         finished_at: row.get("finished_at"),
         phase2_started_at: row.try_get("phase2_started_at").ok().flatten(),
+        generating_thumbnails_started_at: row.try_get("generating_thumbnails_started_at").ok().flatten(),
         stats_json: row.get("stats_json"),
         error_opt: row.get("error_opt"),
         created_at: row.get("created_at"),
@@ -350,7 +353,7 @@ pub async fn get_active_jobs(State(state): State<AppState>) -> Result<Json<Vec<I
     let rows = sqlx::query(
         "SELECT id, library_id, book_id, type, status, started_at, finished_at, stats_json, error_opt, created_at, progress_percent, processed_files, total_files
          FROM index_jobs
-         WHERE status IN ('pending', 'running', 'generating_thumbnails')
+         WHERE status IN ('pending', 'running', 'extracting_pages', 'generating_thumbnails')
          ORDER BY created_at ASC"
     )
     .fetch_all(&state.pool)
@@ -380,7 +383,7 @@ pub async fn get_job_details(
     id: axum::extract::Path<Uuid>,
 ) -> Result<Json<IndexJobDetailResponse>, ApiError> {
     let row = sqlx::query(
-        "SELECT id, library_id, book_id, type, status, started_at, finished_at, phase2_started_at,
+        "SELECT id, library_id, book_id, type, status, started_at, finished_at, phase2_started_at, generating_thumbnails_started_at,
                 stats_json, error_opt, created_at, current_file, progress_percent, total_files, processed_files
          FROM index_jobs WHERE id = $1"
     )