fix(nordagpt): catch plain-text company hallucinations (firma X, również X)

AI bypasses link/bold validation by mentioning companies as plain text
like "firma Baumar" or "również Pro-Bud". New regex catches these patterns
and removes them if the company name isn't in the database.

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

nordabiz_chat.py

@@ -245,7 +245,25 @@ class NordaBizChatEngine:
 
         text = re.sub(r'\*\*([^*]{2,40})\*\*', replace_bold_company, text)
 
-        # 4. Clean up artifacts left by removals
+        # 4. Remove plain-text company name mentions that aren't linked
+        # Catches: "firma Baumar", "również Pro-Bud", "firmy Baumar i Pro-Bud"
+        def replace_plain_company(match):
+            prefix = match.group(1)  # "firma", "również", etc.
+            name = match.group(2).strip().rstrip('.,;:')
+            if name.lower() in valid_names_set:
+                return match.group(0)  # Valid company
+            for vn in valid_names_set:
+                if name.lower() in vn or vn in name.lower():
+                    return match.group(0)  # Partial match
+            logger.warning(f"NordaGPT hallucination blocked: plain text '{name}' after '{prefix}' not in DB")
+            return ''
+
+        text = re.sub(
+            r'(firma|firmą|firmę|firmy|również|oraz)\s+([A-ZĄĘÓŁŹŻŚĆŃ][a-zA-ZąęółźżśćńĄĘÓŁŹŻŚĆŃ-]{2,25}(?:\s+[A-ZĄĘÓŁŹŻŚĆŃ][a-zA-ZąęółźżśćńĄĘÓŁŹŻŚĆŃ-]+)?)',
+            replace_plain_company, text
+        )
+
+        # 5. Clean up artifacts left by removals
         text = re.sub(r':\s*oraz\s*to\b', ': to', text)     # ": oraz to" → ": to"
         text = re.sub(r':\s*,', ':', text)                    # ": ," → ":"
         text = re.sub(r'\*\s*–\s*\n', '\n', text)            # "* – "