chore: tg_filter emoji fix, sprint spec update, tg_digest script

backend/tg_filter.py

@@ -40,7 +40,7 @@ THRESHOLD = 40
 
 # Scan config
 MSGS_PER_GROUP = 500
-GROUPS_PER_CYCLE = 56
+GROUPS_PER_CYCLE = 0  # 0 = scan all eligible groups (was 56)
 
 # Keywords
 INTERESTING_KEYWORDS = [
@@ -146,7 +146,7 @@ async def scan_and_report(dry_run: bool = False) -> list:
         else:
             sorted_candidates.append((cid, title, ""))
     sorted_candidates.sort(key=lambda x: (x[2] == "", x[2]))
-    sorted_candidates = sorted_candidates[:GROUPS_PER_CYCLE]
+    sorted_candidates = sorted_candidates[:len(candidates)] if GROUPS_PER_CYCLE == 0 else sorted_candidates[:GROUPS_PER_CYCLE]
 
     log.info(f"Scanning {len(sorted_candidates)} groups this cycle")
 
@@ -169,7 +169,11 @@ async def scan_and_report(dry_run: bool = False) -> list:
                 sender = None
                 if msg.from_user:
                     sender = msg.from_user.first_name or msg.from_user.username or str(msg.from_user.id)
-                text = (msg.text or msg.caption or "")[:2000]
+                try:
+                    text = (msg.text or msg.caption or "")[:2000]
+                except (UnicodeDecodeError, UnicodeEncodeError):
+                    # surrogate-pass decode failure on certain emoji sequences
+                    text = (str(msg.caption or "")[:2000]) if msg.caption else "[text unreadable]"
                 item = {
                     "chat_id": chat_id, "chat_title": chat_title, "message_id": msg.id,
                     "sender": sender, "text": text, "score": score,