Add debug logging for inventory live-update tracing + cache-bust fetch

Temporary instrumentation to diagnose why InventoryWindow doesn't refresh
on inventory_delta. Three log points:
- useLiveData: logs when inventory_delta arrives and version bump
- InventoryWindow effect: logs every run with state
- InventoryWindow fetch: logs when debounce fires and result count

Also added cache-buster (_t=timestamp) to the refetch URL in case HTTP
caching is masking fresh data.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/src/hooks/useLiveData.ts

@@ -75,15 +75,14 @@ export function useLiveData(): DashboardState {
       const r = msg as RareMessage;
       setRecentRares(prev => [r, ...prev].slice(0, 50));
     } else if (msg.type === 'inventory_delta') {
-      const d = msg as unknown as { character_name: string };
-      // Bump ONLY this character's inventory version so an open window for
-      // that character re-fetches. Deltas for other characters don't touch
-      // it, which keeps the 2s debounce in InventoryWindow from being reset
-      // forever by unrelated chatter.
+      const d = msg as unknown as { character_name: string; action?: string };
+      console.log('[INV_DEBUG] inventory_delta received', { char: d.character_name, action: d.action });
       if (d.character_name) {
         setInventoryVersions(prev => {
           const next = new Map(prev);
-          next.set(d.character_name, (next.get(d.character_name) ?? 0) + 1);
+          const newVer = (next.get(d.character_name) ?? 0) + 1;
+          next.set(d.character_name, newVer);
+          console.log('[INV_DEBUG] bumped version', { char: d.character_name, newVer });
           return next;
         });
       }