chore: cargo fmt + clippy fix for collapsed if-let chain (T017)

- cargo fmt applied across all modified source files
- Collapse nested if let Some / if !is_empty into a single let-chain (clippy::collapsible_match)
- All other warnings are pre-existing dead-code lint on unused trait methods

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

src/database/preview_dao.rs

@@ -4,7 +4,7 @@ use std::ops::DerefMut;
 use std::sync::{Arc, Mutex};
 
 use crate::database::models::{InsertVideoPreviewClip, VideoPreviewClip};
-use crate::database::{connect, DbError, DbErrorKind};
+use crate::database::{DbError, DbErrorKind, connect};
 use crate::otel::trace_db_call;
 
 pub trait PreviewDao: Sync + Send {
@@ -232,10 +232,7 @@ mod tests {
             .unwrap();
 
         // Status should remain "pending" from the first insert
-        let clip = dao
-            .get_preview(&ctx, "photos/video.mp4")
-            .unwrap()
-            .unwrap();
+        let clip = dao.get_preview(&ctx, "photos/video.mp4").unwrap().unwrap();
         assert_eq!(clip.status, "pending");
     }
 
@@ -256,10 +253,7 @@ mod tests {
         )
         .unwrap();
 
-        let clip = dao
-            .get_preview(&ctx, "photos/video.mp4")
-            .unwrap()
-            .unwrap();
+        let clip = dao.get_preview(&ctx, "photos/video.mp4").unwrap().unwrap();
         assert_eq!(clip.status, "complete");
         assert_eq!(clip.duration_seconds, Some(9.5));
         assert_eq!(clip.file_size_bytes, Some(1024000));
@@ -283,10 +277,7 @@ mod tests {
         )
         .unwrap();
 
-        let clip = dao
-            .get_preview(&ctx, "photos/video.mp4")
-            .unwrap()
-            .unwrap();
+        let clip = dao.get_preview(&ctx, "photos/video.mp4").unwrap().unwrap();
         assert_eq!(clip.status, "failed");
         assert_eq!(
             clip.error_message.as_deref(),