feat(sofiia-console): harden cursor pagination with tie-breaker

Version cursor payloads and keep backward compatibility while adding dedicated tie-breaker regression coverage for equal timestamps to prevent pagination duplicates and gaps.

Made-with: Cursor

services/sofiia-console/app/main.py

@@ -3078,7 +3078,8 @@ def _clean_chat_reply(text: str) -> str:
 
 
 def _cursor_encode(payload: Dict[str, Any]) -> str:
-    raw = json.dumps(payload, separators=(",", ":"), ensure_ascii=True).encode("utf-8")
+    wrapped = {"v": 1, **payload}
+    raw = json.dumps(wrapped, separators=(",", ":"), ensure_ascii=True).encode("utf-8")
     return base64.urlsafe_b64encode(raw).decode("ascii")
 
 
@@ -3088,7 +3089,17 @@ def _cursor_decode(cursor: Optional[str]) -> Dict[str, Any]:
     try:
         decoded = base64.urlsafe_b64decode(cursor.encode("ascii")).decode("utf-8")
         data = json.loads(decoded)
-        return data if isinstance(data, dict) else {}
+        if not isinstance(data, dict):
+            return {}
+        # Backward compatibility: accept old cursors without "v".
+        if "v" not in data:
+            return data
+        # Current cursor format version.
+        if int(data.get("v") or 0) == 1:
+            out = dict(data)
+            out.pop("v", None)
+            return out
+        return {}
     except Exception:
         return {}