refactor(pages): 抽取时间选择策略为 TimeSelectMaker，将 Overlay 基类更名为 Dialog

将 findBestTimeOption 中的预约/续约双分支逻辑抽象为策略模式：
- TimeOptionReader 负责从 WebElement 提取时间数据（ReserveTimeReader / RenewTimeReader）
- TimeDecisionMaker 执行纯决策算法，零 Selenium 依赖
- TimeSelectMaker 作为工厂统一创建配置好的决策器
- 共享常量 LIBRARY_CLOSE_MINS 统一收敛至 TimeSelectMaker

同时将 Overlay 基类重命名为 Dialog，SeatMapOverlay 同步更名为 SeatMapDialog，保持命名一致性。

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/pages/flows/_helpers.py

@@ -7,9 +7,6 @@ This software is provided "as is", without any warranty of any kind.
 You may use, modify, and distribute this file under the terms of the MIT License.
 See the LICENSE file for details.
 """
-from datetime import datetime
-
-
 def timeStrToMins(
     time_str: str,
 ) -> int:
@@ -17,67 +14,9 @@ def timeStrToMins(
     hour, minute = map(int, time_str.split(":"))
     return hour * 60 + minute
 
-
 def minsToTimeStr(
     mins: int,
 ) -> str:
 
     hour, minute = divmod(int(mins), 60)
     return f"{hour:02d}:{minute:02d}"
-
-
-def findBestTimeOption(
-    time_options: list,
-    target_time: int,
-    max_time_diff: int,
-    prefer_earlier: bool,
-    is_reserve: bool = True,
-) -> tuple:
-    """
-        Find the best time option from available WebElement options.
-
-        Returns:
-            (bestElement, bestText, actual_diff, freeTimesList)
-            or (None, None, None, freeTimesList) if no suitable option.
-    """
-
-    free_times = []
-    best_time_diff = max_time_diff
-    best_actual_diff = None
-    best_time_opt = None
-
-    for time_opt in time_options:
-        if is_reserve:
-            time_attr = time_opt.get_attribute("time")
-            if time_attr == "now":
-                now = datetime.now()
-                time_val = now.hour * 60 + now.minute
-            elif time_attr and time_attr.isdigit():
-                time_val = int(time_attr)
-            else:
-                continue
-        else:
-            time_attr = time_opt.get_attribute("id")
-            if not (time_attr and time_attr.isdigit()):
-                continue
-            time_val = int(time_attr)
-        free_times.append(
-            time_opt.text.strip()
-            if not is_reserve
-            else minsToTimeStr(time_val)
-        )
-        actual_diff = time_val - target_time
-        abs_diff = abs(actual_diff)
-        if abs_diff < best_time_diff or (
-            abs_diff == best_time_diff
-            and (
-                (prefer_earlier and actual_diff <= 0)
-                or (not prefer_earlier and actual_diff >= 0)
-            )
-        ):
-            best_time_diff = abs_diff
-            best_actual_diff = actual_diff
-            best_time_opt = time_opt
-    if best_time_opt is not None:
-        return (best_time_opt, best_time_opt.text.strip(), best_actual_diff, free_times)
-    return (None, None, None, free_times)