refactor: tighten upload and viewer contracts

lib/upload-staging.ts

@@ -3,7 +3,7 @@ import { dirname, join } from 'path'
 import { mkdir, readdir, readFile, rm, writeFile } from 'fs/promises'
 import { existsSync } from 'fs'
 import { TMP_DIR } from '@/lib/constants'
-import { isRecord } from '@/lib/guards'
+import { getErrorMessage, isRecord } from '@/lib/guards'
 import { getModelAssetPath } from '@/lib/model-paths'
 import { prepareGitAssets } from '@/lib/prepare-git-assets'
 import type {
@@ -28,7 +28,7 @@ interface StagedOriginalFile {
 interface StagedPreparedData {
   modelFilename: string
   compressed: boolean
-  deliveryMode?: GitModelMode
+  deliveryMode: GitModelMode
   compressionError?: string
   assetSummaries: PreparedAssetSummary[]
 }
@@ -94,7 +94,7 @@ function isStagedPreparedData(value: unknown): value is StagedPreparedData {
   return isRecord(value)
     && typeof value.modelFilename === 'string'
     && typeof value.compressed === 'boolean'
-    && (value.deliveryMode === undefined || isGitModelMode(value.deliveryMode))
+    && isGitModelMode(value.deliveryMode)
     && (value.compressionError === undefined || typeof value.compressionError === 'string')
     && Array.isArray(value.assetSummaries)
     && value.assetSummaries.every(isPreparedAssetSummary)
@@ -146,8 +146,14 @@ async function cleanupExpiredStagingUploads() {
       if (now - manifest.createdAt > STAGING_TTL_MS) {
         await cleanupStagingUpload(stagingId)
       }
-    } catch {
-      await cleanupStagingUpload(stagingId).catch(() => {})
+    } catch (err) {
+      await cleanupStagingUpload(stagingId).catch((cleanupErr) => {
+        console.warn('[WARN] Staging cleanup failed', {
+          stagingId,
+          error: getErrorMessage(cleanupErr),
+          originalError: getErrorMessage(err),
+        })
+      })
     }
   }
 }
@@ -259,7 +265,7 @@ export async function ensurePreparedStagingAssets(stagingId: string): Promise<Pr
     modelFilename: manifest.prepared.modelFilename,
     assetSummaries: manifest.prepared.assetSummaries,
     compressed: manifest.prepared.compressed,
-    deliveryMode: manifest.prepared.deliveryMode ?? manifest.gitModelMode,
+    deliveryMode: manifest.prepared.deliveryMode,
     compressionError: manifest.prepared.compressionError,
   }
 }