fix: Improved duplicate prevention in cast iron scanner

- Better link normalization and checking
- Skip items already in seen_links with logging
- Clean up state file to last 500 items
- Always mark items as seen (deal or not)
- Added logging for skipped duplicates

Also: eBay scraping temporarily blocked/changed - investigating

agents/reddit-scout/state/scout-state.json

@@ -114,8 +114,15 @@
     "1sgqzb9",
     "1sgosjw",
     "1shf8nt",
-    "1sh34bf"
+    "1sh34bf",
+    "1shvh2y",
+    "1shtzie",
+    "1shsg8u",
+    "1shr186",
+    "1shqvf5",
+    "1shn1jg",
+    "1shm8fy"
   ],
-  "total_scanned": 1400,
-  "total_matches": 35
+  "total_scanned": 1450,
+  "total_matches": 39
 }