Switch default model to qwen3 and add intent routing for reliable tool calling

Mistral didn't reliably use Ollama's structured tool calling API — it wrote
tool calls as JSON text instead of invoking them. This adds an intent routing
layer that classifies user intent via a fast non-streaming LLM call before
streaming, executing detected tools directly and bypassing native tool calling.

- Change default OLLAMA_MODEL from mistral to qwen3
- Add intent.py: classify_intent() with JSON parsing and fallback regex
- Integrate intent routing into generation_task.py round 0
- Add all-day event support (iCalendar DATE values) to CalDAV service
- Add recurring event support (RRULE) to CalDAV service and tool definition
- Improve create_event tool description for descriptive titles
- Enhance system prompt with structured tool usage guidance

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

src/fabledassistant/services/caldav.py

@@ -2,7 +2,7 @@
 
 import asyncio
 import logging
-from datetime import datetime, timedelta
+from datetime import date as date_type, datetime, timedelta
 
 import caldav
 import icalendar
@@ -76,30 +76,61 @@ async def create_event(
     duration: int | None = None,
     description: str | None = None,
     location: str | None = None,
+    all_day: bool = False,
+    recurrence: str | None = None,
 ) -> dict:
-    """Create a calendar event. start/end are ISO datetime strings."""
+    """Create a calendar event.
+
+    start/end are ISO date (YYYY-MM-DD) or datetime strings.
+    If all_day is True, DTSTART/DTEND use DATE values.
+    recurrence is an iCalendar RRULE string (e.g. "FREQ=YEARLY").
+    """
     config = await get_caldav_config(user_id)
     if not (config.get("caldav_url") and config.get("caldav_username") and config.get("caldav_password")):
         raise ValueError("CalDAV is not configured. Go to Settings → Calendar to set it up.")
 
-    dt_start = datetime.fromisoformat(start)
-    if end:
-        dt_end = datetime.fromisoformat(end)
-    else:
-        dt_end = dt_start + timedelta(minutes=duration or 60)
-
     cal = icalendar.Calendar()
     cal.add("prodid", "-//FabledAssistant//EN")
     cal.add("version", "2.0")
 
     event = icalendar.Event()
     event.add("summary", title)
-    event.add("dtstart", dt_start)
-    event.add("dtend", dt_end)
+
+    if all_day:
+        # All-day events use DATE values (no time component)
+        d_start = datetime.fromisoformat(start).date() if "T" in start else date_type.fromisoformat(start)
+        if end:
+            d_end = datetime.fromisoformat(end).date() if "T" in end else date_type.fromisoformat(end)
+        else:
+            d_end = d_start + timedelta(days=1)
+        event.add("dtstart", d_start)
+        event.add("dtend", d_end)
+        result_start = d_start.isoformat()
+        result_end = d_end.isoformat()
+    else:
+        dt_start = datetime.fromisoformat(start)
+        if end:
+            dt_end = datetime.fromisoformat(end)
+        else:
+            dt_end = dt_start + timedelta(minutes=duration or 60)
+        event.add("dtstart", dt_start)
+        event.add("dtend", dt_end)
+        result_start = dt_start.isoformat()
+        result_end = dt_end.isoformat()
+
     if description:
         event.add("description", description)
     if location:
         event.add("location", location)
+    if recurrence:
+        # Parse RRULE string like "FREQ=YEARLY" into a vRecur dict
+        rrule_parts = {}
+        for part in recurrence.split(";"):
+            if "=" in part:
+                key, value = part.split("=", 1)
+                rrule_parts[key.strip().lower()] = value.strip()
+        event.add("rrule", rrule_parts)
+
     cal.add_component(event)
 
     ical_str = cal.to_ical().decode("utf-8")
@@ -111,11 +142,15 @@ async def create_event(
 
     await asyncio.to_thread(_save)
 
-    return {
+    result = {
         "title": title,
-        "start": dt_start.isoformat(),
-        "end": dt_end.isoformat(),
+        "start": result_start,
+        "end": result_end,
+        "all_day": all_day,
     }
+    if recurrence:
+        result["recurrence"] = recurrence
+    return result
 
 
 async def list_events(user_id: int, date_from: str, date_to: str) -> list[dict]: