Fix completed-history owner receipts and verified attachment cleanup

Use truthful storage absence receipts for MCP deletion and preserve replay fences. Qualify retained chat controls and provider submissions through their actual owners, retain voice and registration obligations, and bound delivery receipt lookup.

Co-Authored-By: Paperclip <noreply@paperclip.ing>

server/src/storage/local-disk-provider.ts

@@ -30,8 +30,10 @@ function resolveWithin(baseDir: string, objectKey: string): string {
 async function statOrNull(filePath: string) {
   try {
     return await fs.stat(filePath);
-  } catch {
-    return null;
+  } catch (error) {
+    const code = (error as NodeJS.ErrnoException | null)?.code;
+    if (code === "ENOENT" || code === "ENOTDIR") return null;
+    throw error;
   }
 }
 
@@ -89,8 +91,9 @@ export function createLocalDiskStorageProvider(baseDir: string): StorageProvider
       const filePath = resolveWithin(root, input.objectKey);
       try {
         await fs.unlink(filePath);
-      } catch {
-        // idempotent delete
+      } catch (error) {
+        const code = (error as NodeJS.ErrnoException | null)?.code;
+        if (code !== "ENOENT" && code !== "ENOTDIR") throw error;
       }
     },
   };