Integrated, working.

This integrates the liteq, and it prevents duplicates in a way that
matches my use-case.

I might try and push things back out to a separate module, but for now,
this will do.

internal/liteq/db/queries.sql

@@ -20,10 +20,9 @@ VALUES
         unixepoch(),
         ?,
         ?
-    ) ON CONFLICT (deduping_key, job_status)
+    ) ON CONFLICT (deduping_key)
 WHERE
-    deduping_key != ''
-    AND (job_status = 'queued' OR job_status = 'fetched' OR job_status = 'completed') DO NOTHING;
+    deduping_key != '' DO NOTHING;
 
 -- name: doQueueJobReplaceDupe :exec
 INSERT INTO