fix(vuln): flush negative auto-resolve cache on mappings reload

ResetAutoResolveFailedCache() was documented as "called when seed/community
mappings are reloaded" but had no callers, so the 7-day NVD-miss cache
survived every reseed. Software that previously missed stayed blacklisted
against the warm Function instance and never got a fresh resolution attempt
against the reloaded mappings.

Fold the negative-cache flush into ResetMappingsCache() so all 7 reload
sites (reseed seed/community, save/delete/bulk-auto-resolve custom mappings)
clear it — no call site can forget it.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/Backend/AutopilotMonitor.Functions/Services/Vulnerability/VulnerabilityCorrelationService.cs

@@ -64,10 +64,14 @@ namespace AutopilotMonitor.Functions.Services.Vulnerability
         /// Resets the static mappings cache so the next call to EnsureMappingsLoadedAsync
         /// reloads all mappings (seed, custom, community) from their sources.
         /// Called after reseed operations that update community mappings in table storage.
+        /// Also flushes the negative auto-resolve cache so software that previously missed
+        /// gets a fresh resolution attempt against the reloaded mappings — otherwise stale
+        /// NVD-miss entries would suppress retries for up to <see cref="AutoResolveFailedCacheDays"/> days.
         /// </summary>
         public static void ResetMappingsCache()
         {
             _seedLoaded = false;
+            ResetAutoResolveFailedCache();
         }
 
         public async Task<Dictionary<string, object>?> CorrelateAsync(