fix(briefing): stale weather auto-refresh + task filter + overdue prompt

Three briefing quality fixes surfaced by reading today's 2026-04-11
compilation output:

- **Stale weather**: get_weather was returning 48h-old cache data
  after a missed scheduler run. Tool now auto-refreshes any cached
  location older than 6h (fetching fresh data from Open-Meteo), and
  stamps each location with cache_age_hours + is_stale so the model
  can hedge instead of faithfully relaying old numbers.

- **Cancelled tasks leaking into prose**: briefing loop now defaults
  list_tasks calls to status=["todo","in_progress"] when the model
  doesn't specify, so cancelled/done items stop showing up in the
  summary. Localized to the briefing path — chat still sees full
  history.

- **Overdue in-progress tasks missed by midday check-in**: tightened
  the check-in prompt to explicitly require two list_tasks calls —
  one for in_progress (catches items dragging past their due date)
  and one filtered by due date — so long-running tasks stop getting
  silently dropped.

src/fabledassistant/services/briefing_pipeline.py

@@ -106,6 +106,10 @@ def _agentic_system_prompt(
             f"You are the user's personal assistant giving a brief {slot} check-in. "
             "Use tools to see what's changed since this morning. Focus on progress and "
             "what's still unaddressed.\n\n"
+            "When checking tasks, call list_tasks at least twice:\n"
+            "- once with status=\"in_progress\" to see anything already being worked on "
+            "(regardless of due date — these can quietly drag past their due dates)\n"
+            "- once filtered by due date for what's coming up or overdue today\n\n"
             "Rules:\n"
             "- Call tools to see current state. Never assert facts without tool results.\n"
             "- If nothing meaningful has changed, say so briefly — don't invent progress.\n"
@@ -239,6 +243,12 @@ async def run_agentic_briefing(
                 except Exception:
                     arguments = {}
 
+            # Default list_tasks to active statuses only so cancelled/done
+            # items don't slip into briefing prose. The model can still
+            # pass an explicit status filter when it wants something else.
+            if tool_name == "list_tasks" and not arguments.get("status"):
+                arguments["status"] = ["todo", "in_progress"]
+
             try:
                 if tool_name == "get_rss_items" and rss_override is not None:
                     # Use topic-scored/filtered items already computed by