feat: fetcher 支援多 target union 掃描

- 新增 RADAR_TARGETS 環境變數（'name:lat,lng;...'）
- 未設時 fall back 到單點 RADAR_LAT/LNG（backward-compat）
- 主流程改為 loop 每個 target 呼叫 Function Server，以 (id, lat, lng, expire_time) dedupe 後 union
- 單點失敗不阻斷其他 target（try/except 包起來）
- debug 記錄每 target 原始筆數與完整 targets 清單
- 搭配 RADAR_ZOOM=15 解決 zoom 11 廣視角下單位面積密度過低的問題

本機驗證：5 target（台北/內湖/板橋/新竹/宜蘭）union 191 筆，
twpk 內湖南港街區 bounds（zoom 17 視角）從 0 筆變 2 筆。

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

radar_fetcher.py

@@ -29,7 +29,10 @@ UA_FROM_STATE = os.getenv("UA_FROM_STATE", "true").lower() in ("1", "true", "yes
 RADAR_LAT = float(os.getenv("RADAR_LAT", "25.0478"))
 RADAR_LNG = float(os.getenv("RADAR_LNG", "121.5170"))
 
-# ✅ 對齊 fetch_and_upload.sh：ZOOM=11
+# 多點掃描：'name:lat,lng;name2:lat2,lng2;...'。未設時 fall back 到 RADAR_LAT/LNG 單點
+RADAR_TARGETS = os.getenv("RADAR_TARGETS", "").strip()
+
+# ✅ 對齊 fetch_and_upload.sh：ZOOM=11（多點模式建議改 15）
 RADAR_ZOOM = int(os.getenv("RADAR_ZOOM", "11"))
 
 RADAR_SHOT = os.getenv("RADAR_SHOT", "false").lower() in ("1", "true", "yes", "y")
@@ -223,6 +226,26 @@ def _postprocess(
     return out
 
 
+def _parse_targets() -> List[tuple]:
+    """解析 RADAR_TARGETS；未設時 fall back 單點 RADAR_LAT/LNG。
+    格式：'name:lat,lng;name2:lat2,lng2;...'
+    """
+    if not RADAR_TARGETS:
+        return [("default", RADAR_LAT, RADAR_LNG)]
+    targets = []
+    for chunk in RADAR_TARGETS.split(";"):
+        chunk = chunk.strip()
+        if not chunk:
+            continue
+        name, _, coord = chunk.partition(":")
+        lat_s, _, lng_s = coord.partition(",")
+        try:
+            targets.append((name.strip(), float(lat_s), float(lng_s)))
+        except ValueError:
+            logger.warning(f"skip malformed RADAR_TARGETS entry: {chunk}")
+    return targets or [("default", RADAR_LAT, RADAR_LNG)]
+
+
 def _cache_to_redis(payload: Dict[str, Any]) -> None:
     r = redis.Redis(
         host=REDIS_HOST,
@@ -240,27 +263,38 @@ def _cache_to_redis(payload: Dict[str, Any]) -> None:
 
 def main() -> int:
     try:
+        targets = _parse_targets()
         logger.info(
-    "ENV: RADAR_ZOOM={}, MIN_REMAINING={}, PERFECT_ONLY={}, UA_FROM_STATE={}, SCRIPT_PATH={}, STATE_PATH={}".format(
-        os.getenv("RADAR_ZOOM"),
-        os.getenv("MIN_REMAINING"),
-        os.getenv("PERFECT_ONLY"),
-        os.getenv("UA_FROM_STATE"),
-        SCRIPT_PATH,
-        STATE_PATH,
-    )
-)
+            "ENV: RADAR_ZOOM={}, MIN_REMAINING={}, PERFECT_ONLY={}, UA_FROM_STATE={}, targets={}".format(
+                RADAR_ZOOM, MIN_REMAINING, PERFECT_ONLY, UA_FROM_STATE, len(targets),
+            )
+        )
 
+        script_text = _load_script_text(SCRIPT_PATH)
+        state_injected = _inject_state(script_text, STATE_PATH, UA_FROM_STATE)
 
-        code = _load_script_text(SCRIPT_PATH)
-        code = _inject_target_and_shot(code, RADAR_LAT, RADAR_LNG, RADAR_ZOOM, RADAR_SHOT)
-        code = _inject_state(code, STATE_PATH, UA_FROM_STATE)
+        all_raw: Dict[Any, Dict[str, Any]] = {}  # dedupe by (id, lat, lng, expire_time)
+        merged_notes: List[str] = []
+        target_stats: List[str] = []
 
-        parsed = _call_function_server(code)
-        raw_items = parsed.get("results", [])
-        debug = parsed.get("debug", {})
+        for i, (name, lat, lng) in enumerate(targets, 1):
+            logger.info(f"[{i}/{len(targets)}] fetching '{name}' at ({lat},{lng}) zoom={RADAR_ZOOM}")
+            try:
+                code = _inject_target_and_shot(state_injected, lat, lng, RADAR_ZOOM, RADAR_SHOT)
+                parsed = _call_function_server(code)
+                raw_items = parsed.get("results", [])
+                target_stats.append(f"{name}:{len(raw_items)}")
+                for r in raw_items:
+                    key = (r.get("id"), r.get("latitude"), r.get("longitude"), r.get("expire_time"))
+                    all_raw.setdefault(key, r)
+                notes = parsed.get("debug", {}).get("notes", []) if isinstance(parsed.get("debug"), dict) else []
+                merged_notes.extend(f"[{name}] {n}" for n in notes)
+            except Exception as e:
+                logger.exception(f"[{i}/{len(targets)}] '{name}' failed: {e}")
+                target_stats.append(f"{name}:ERROR")
 
-        logger.info(f"Got {len(raw_items)} results (before filters)")
+        raw_items = list(all_raw.values())
+        logger.info(f"union total {len(raw_items)} unique (per-target: {', '.join(target_stats)})")
 
         filtered = _postprocess(
             raw_items,
@@ -270,7 +304,6 @@ def main() -> int:
             species=SPECIES,
         )
 
-        # ✅ filtered=0 時印出原因線索（remaining/perfect）
         if raw_items and not filtered:
             rems = [r.get("remaining") for r in raw_items if r.get("remaining") is not None]
             perfects = sum(1 for r in raw_items if r.get("is_perfect"))
@@ -290,8 +323,10 @@ def main() -> int:
             "count_filtered": len(filtered),
             "items": filtered,
             "debug": {
-                **(debug if isinstance(debug, dict) else {}),
-                "api_source": "Fresh from Function Server",
+                "notes": merged_notes,
+                "targets": [f"{n}:{la},{ln}" for n, la, ln in targets],
+                "target_stats": target_stats,
+                "api_source": "Fresh from Function Server (multi-target union)",
             },
         }