Enhance: generate 32-bit seeds

SeedVR2VideoUpscaler (the new Sharpen / Rescue templates) rejects seeds
above 2^32 - 1 at validation, and the 52-bit seeds made every job fail with
"Value ... bigger than max of 4294967295: seed". 32 bits is still plenty of
variety for the Fibo templates.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/enhance/service.rs

@@ -16,7 +16,7 @@ use serde::{Deserialize, Serialize};
 use super::comfy::{ApproveError, ComfyClient, ComfyError, HistoryEntry, Staged, SubmitError};
 use super::config::{EnhanceConfig, Loaded, PromptMode};
 use super::path_map::PathMap;
-use super::template::Template;
+use super::template::{Template, random_seed};
 use crate::database::enhance_dao::{
     EnhanceJobDao, EnhanceJobRow, JobUpdate, RecentPrompt, STATUS_APPROVED, STATUS_EXPIRED,
     STATUS_FAILED, STATUS_QUEUED, STATUS_READY, STATUS_RUNNING, STATUS_UNAVAILABLE,
@@ -314,9 +314,7 @@ impl EnhanceService {
             None => None,
         };
         let filled = template
-            .fill(&source, prompt, reference_path.as_deref(), &mut || {
-                rand::random::<u64>() >> 12
-            })
+            .fill(&source, prompt, reference_path.as_deref(), &mut random_seed)
             .map_err(|e| EnhanceError::BadRequest(e.0))?;
 
         if !self.probe_now().await {