refactor: update AppState references to use state module

- Change all instances of AppState to reference the new state module across multiple files for consistency.
- Clean up imports in auth, books, index_jobs, libraries, pages, search, settings, thumbnails, and tokens modules.
- Simplify main.rs by removing unused code and organizing middleware and route handlers under the new handlers module.

apps/indexer/src/scheduler.rs

@@ -0,0 +1,67 @@
+use anyhow::Result;
+use sqlx::{PgPool, Row};
+use tracing::info;
+use uuid::Uuid;
+
+pub async fn check_and_schedule_auto_scans(pool: &PgPool) -> Result<()> {
+    let libraries = sqlx::query(
+        r#"
+        SELECT id, scan_mode, last_scan_at
+        FROM libraries
+        WHERE monitor_enabled = TRUE
+          AND (
+            next_scan_at IS NULL
+            OR next_scan_at <= NOW()
+          )
+          AND NOT EXISTS (
+            SELECT 1 FROM index_jobs
+            WHERE library_id = libraries.id
+              AND status IN ('pending', 'running')
+          )
+        "#
+    )
+    .fetch_all(pool)
+    .await?;
+
+    for row in libraries {
+        let library_id: Uuid = row.get("id");
+        let scan_mode: String = row.get("scan_mode");
+        
+        info!("[SCHEDULER] Auto-scanning library {} (mode: {})", library_id, scan_mode);
+        
+        let job_id = Uuid::new_v4();
+        let job_type = match scan_mode.as_str() {
+            "full" => "full_rebuild",
+            _ => "rebuild",
+        };
+        
+        sqlx::query(
+            "INSERT INTO index_jobs (id, library_id, type, status) VALUES ($1, $2, $3, 'pending')"
+        )
+        .bind(job_id)
+        .bind(library_id)
+        .bind(job_type)
+        .execute(pool)
+        .await?;
+        
+        // Update next_scan_at
+        let interval_minutes = match scan_mode.as_str() {
+            "hourly" => 60,
+            "daily" => 1440,
+            "weekly" => 10080,
+            _ => 1440, // default daily
+        };
+        
+        sqlx::query(
+            "UPDATE libraries SET last_scan_at = NOW(), next_scan_at = NOW() + INTERVAL '1 minute' * $2 WHERE id = $1"
+        )
+        .bind(library_id)
+        .bind(interval_minutes)
+        .execute(pool)
+        .await?;
+        
+        info!("[SCHEDULER] Created job {} for library {}", job_id, library_id);
+    }
+    
+    Ok(())
+}