fix: address code review feedback

- Fix missing import for compute_filename_for_reference in ingest.py
- Apply code review fixes across routes, queries, scanner, seeder,
  hashing, ingest, path_utils, main, and server
- Update and add tests for sync references and seeder

Amp-Thread-ID: https://ampcode.com/threads/T-019cb61a-ed54-738c-a05f-9b5242e513f3
Co-authored-by: Amp <amp@ampcode.com>

main.py

@@ -259,10 +259,10 @@ def prompt_worker(q, server_instance):
                 extra_data[k] = sensitive[k]
 
             asset_seeder.pause()
-
-            e.execute(item[2], prompt_id, extra_data, item[4])
-
-            asset_seeder.resume()
+            try:
+                e.execute(item[2], prompt_id, extra_data, item[4])
+            finally:
+                asset_seeder.resume()
             need_gc = True
 
             remove_sensitive = lambda prompt: prompt[:5] + prompt[6:]