fix(persona): forbid dismissive openers + fix script for '..' and negative tails

- persona_prompts OPENER RULE: never open with dots/ellipsis and never end
  an opener by dismissing/belittling the product (but ไม่คิดจะซื้อ, แค่มาดูเล่น,
  ก็แค่มาเมิน, ไม่ได้จะซื้อ...) — Thai openers stay politely interested
- fix_openers.py: strip leading dots("..") and remove trailing dismissive
  clauses ('ตามไม่คิดจะซื้อหรอกนะ' etc.) so existing personas are normalized
  to a natural interest opener; update docstring

backend/app/services/persona_prompts.py

@@ -56,6 +56,9 @@ RULES:
    do NOT open with casual English-style interjections or filler like "เฮ้", "เอ้", "เอ่อ", "hey", "hi ya", or
    singsong slang ("ไง", "นี่ๆ", "ว่าไง"). A question that gets to the point directly is ideal. For English,
    a plain "Hi" or "Hello" is fine.
+   NEVER open with ellipsis/dots ("..", "..."), and NEVER end the opener by dismissing or downgrading the
+   product — e.g. do NOT write "แต่ไม่คิดจะซื้อหรอกนะ", "แค่มาดูเล่น", "ก็แค่มาเมิน", "ไม่ได้จะซื้อ", "แต่กะแค่ลองดู".
+   An opener must show polite interest or ask a question; it must NOT pre-dismiss or belittle the product.
    NEVER make the opener a complaint, a refusal, a price grumble, a "never mind", or anything negative — the
    customer's resistance must only surface DURING the conversation, not in their very first message.
 9. Language: output all human text in the requested language.

backend/scripts/fix_openers.py

@@ -1,13 +1,16 @@
 """One-time data fix (run in the EasyPanel container console):
 Rewrite existing personas' openers (opener) to natural Thai.
 
-Only rewords openers that OPEN with a casual interjection/filler
-(เฮ้ / เอ้ / เอ่อ / เอ๊ะ / อืม / เออ / นี่ๆ / ว่าไง / hey / hi / hiya / yo ...).
+Only rewords openers that:
+  - open with a casual interjection/filler (เฮ้ / เอ้ / เอ่อ / hey / hi / yo ...),
+  - open with ellipsis/dots ("..", "..."), or
+  - end with a dismissive clause Thais would not say first
+    ("แต่ไม่คิดจะซื้อหรอกนะ", "ไม่ได้จะซื้อ", "แค่มาดูเล่น", "ก็แค่มาเมิน"...).
 Everyone else is left untouched (safe & reversible). Prints before -> after.
 
 Usage:
   cd /app/backend
-  python3 /path/to/fix_openers.py        # or paste as a heredoc
+  python3 scripts/fix_openers.py
 """
 from __future__ import annotations
 
@@ -30,6 +33,15 @@ FILLER = re.compile(
 )
 BARE_POLITE = re.compile(r"^(ครับ|ค่ะ)(\s|$)")
 THAI_CHAR = re.compile(r"[\u0E00-\u0E7F]")
+# Leading punctuation/dots ("..", "...") that look unfinished/un-natural.
+LEAD_DOTS = re.compile(r"^[\.…\s]*")
+# Trailing dismissive clauses Thais would not say in an opener
+# ("แต่ไม่คิดจะซื้อหรอกนะ", "ไม่ได้จะซื้อ", "แค่มาดูเล่น", "ก็แค่มาเมิน"...).
+DISMISS_TAIL = re.compile(
+    r"\s*(?:แต่(?:ก็)?(?:ไม่(?:ได้)?คิดจะซื้อ|ไม่รู้จะซื้อ|ไม่ได้จะซื้อ|ไม่ตั้งใจซื้อ)|"
+    r"แค่(?:มา)?ดู(?:เล่น)?|ก็แค่(?:มา)?ดู(?:เล่น)?|ก็แค่มาเมิน|"
+    r"แต่กะแค่ลองดู|ก็แค่ลองดู)(?:หรอกนะ|หรอก|นะ|ล่ะ)?$"
+)
 
 
 def fix_opener(existing: str) -> str | None:
@@ -41,17 +53,23 @@ def fix_opener(existing: str) -> str | None:
     if not THAI_CHAR.search(s):
         return None
 
-    # 1) Strip leading casual fillers (เฮ้ / เอ้ / เอ่อ / hey / hi / ...).
-    m = FILLER.match(s)
-    grand_rest = s[m.end():].strip(" ,-–—:;") if m else s.strip()
-    new = grand_rest
+    # 0) Strip leading dots/ellipsis and any casual filler.
+    new = LEAD_DOTS.sub("", s)
+    m = FILLER.match(new)
+    if m:
+        new = new[m.end():]
+    new = new.strip(" .…,:-–—;")
 
-    # 2) If it now (or originally) opens with a bare politeness word, prepend
-    #    the proper greeting: "ครับ สนใจ..."  ->  "สวัสดีครับ สนใจ..."
+    # 1) Remove a trailing dismissive clause ("แต่ไม่คิดจะซื้อหรอกนะ" etc.),
+    #    so the opener stays politely interested instead of pre-dismissing.
+    new = DISMISS_TAIL.sub("", new).strip(" .…,:-–—;")
+
+    # 2) If it now opens with a bare politeness word, prepend the greeting:
+    #    "ครับ สนใจ..."  ->  "สวัสดีครับ สนใจ..."
     bp = BARE_POLITE.match(new)
     if bp:
         polite = new[: len(bp.group(1))]
-        new = new[len(polite):].strip(" ,-–—:;") or ""
+        new = new[len(polite):].strip(" .…,:-–—;") or ""
         new = "สวัสดี" + polite + ((" " + new) if new else "")
 
     cleaned = " ".join(new.split())