fix: minichat markdown rendering and weather temperature unit preference

- KnowledgeView minichat: render assistant messages through renderMarkdown
  so headers, bold, lists etc. display correctly instead of raw markdown
- get_weather tool: read user's temp_unit from briefing_config and convert
  temperatures to °F when preferred; also include temp_unit in the
  returned payload so the model can label values correctly

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/fabledassistant/services/tools.py

@@ -1914,20 +1914,34 @@ async def execute_tool(
             from fabledassistant.services.weather import (
                 get_cached_weather, geocode, _fetch_open_meteo, parse_forecast
             )
+            from fabledassistant.services.briefing_pipeline import _get_temp_unit
             from datetime import timezone as _tz
             location = (arguments.get("location") or "").strip()
+            temp_unit = await _get_temp_unit(user_id)
+
+            def _apply_unit(days: list[dict]) -> list[dict]:
+                if temp_unit != "F":
+                    return days
+                def _c_to_f(v: float | None) -> float | None:
+                    return round(v * 9 / 5 + 32, 1) if v is not None else None
+                return [
+                    {**d, "temp_max": _c_to_f(d.get("temp_max")), "temp_min": _c_to_f(d.get("temp_min"))}
+                    for d in days
+                ]
+
             _known = {"home", "work", "all", ""}
             if location.lower() not in _known:
                 # Live geocode + fetch for arbitrary city
                 try:
                     lat, lon, label = await geocode(location)
                     raw = await _fetch_open_meteo(lat, lon)
-                    days = parse_forecast(raw)
+                    days = _apply_unit(parse_forecast(raw))
                     return {"success": True, "data": {"locations": [{
                         "location_key": "query",
                         "location_label": label,
                         "fetched_at": datetime.now(_tz.utc).isoformat(),
                         "days": days,
+                        "temp_unit": temp_unit,
                         "changes_since_last_fetch": [],
                     }]}}
                 except Exception as e:
@@ -1936,6 +1950,10 @@ async def execute_tool(
             locations = await get_cached_weather(user_id)
             if location.lower() not in ("all", ""):
                 locations = [loc for loc in locations if loc["location_key"] == location.lower()]
+            locations = [
+                {**loc, "days": _apply_unit(loc.get("days", [])), "temp_unit": temp_unit}
+                for loc in locations
+            ]
             return {"success": True, "data": {"locations": locations}}
 
         elif tool_name == "get_rss_items":