Fix weekly schedule starting from today instead of Monday (#18)

The handler passed `now` as start_date, so mid-week runs showed
14 days from today instead of Mon–Sun x2. Also, day names were
derived from a static index (DAY_ORDER[i%7]) which assumed
index 0 = Monday — when start_date wasn't Monday, Saturday and
Sunday were mislabeled as Monday and Tuesday.

Fix: pass this week's Monday from the handler, and derive day
names from the actual date via strftime instead of a static list.

Fixes #17

src/blocks.py

@@ -5,7 +5,6 @@ from zoneinfo import ZoneInfo
 
 EASTERN = ZoneInfo("America/New_York")
 
-DAY_ORDER = ["Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", "Sunday"]
 WEEKEND_DAYS = {"Saturday", "Sunday"}
 
 
@@ -47,7 +46,7 @@ def build_week_schedule(schedule, start_date: datetime | None = None) -> list[di
             lines.append("")  # visual separator between weeks
         date = start_date + timedelta(days=i)
         date_str = date.strftime("%Y-%m-%d")
-        day_name = DAY_ORDER[i % 7]
+        day_name = date.strftime("%A")
         is_today = date_str == today_str
 
         # Weekend day shift (8am–5pm)

src/weekly_post.py

@@ -172,10 +172,11 @@ def handler(event, context):
         # Email pay summary to payroll
         _send_pay_email(week_label, pay_record)
 
-    # --- Two-week schedule ---
-    blocks = build_week_schedule(schedule, start_date=now)
+    # --- Two-week schedule (always starts on Monday of this week) ---
+    this_monday = now - timedelta(days=now.weekday())
+    blocks = build_week_schedule(schedule, start_date=this_monday)
 
-    end_date = now + timedelta(days=13)
+    end_date = this_monday + timedelta(days=13)
     slack.chat_postMessage(
         channel=channel_id,
         blocks=blocks,