Harden JSON event parsing and broadcast message formatting

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <[email protected]>

lib/parser.py

@@ -84,7 +84,7 @@ class EventParser:
         except json.JSONDecodeError as e:
             logger.debug(f'JSON decode error: {e}')
             return None
-        except (KeyError, TypeError) as e:
+        except (KeyError, TypeError, ValueError) as e:
             logger.debug(f'Error parsing event: {e}')
             return None
 
@@ -212,7 +212,6 @@ class EventParser:
             else:
                 weapon_name = WEAPON_NAMES.get(weapon, weapon)
                 return f"{score_prefix}{killer_prefix}^8{killer_name}^0 ^7committed suicide with the ^7{weapon_name}{warmup}\n"
-            return None
 
         # Regular kill: +1 for killer
         if not data.get('WARMUP', False):