Fix issues #8, #9, #10, #11: scheduling conflicts, med reminders, adaptive timing, nagging

- #11: Add validation to prevent simultaneous scheduling of routines and medications
  - Added _check_schedule_conflicts() in routines.py
  - Added _check_med_schedule_conflicts() in medications.py
  - Returns HTTP 409 with descriptive error on conflict

- #10: Fix medication reminders not being sent
  - Added call to check_adaptive_medication_reminders() in daemon poll loop

- #9: Fix can't enable adaptive timing
  - Added proper error handling and logging in update_adaptive_settings()
  - Returns meaningful error message on database failures

- #8: Fix nagging not working
  - Added debug logging for missing settings
  - Auto-create medication schedules if they don't exist
  - Improved error logging (warning -> error)

api/routes/medications.py

@@ -2,6 +2,7 @@
 Medications API - medication scheduling, logging, and adherence tracking
 """
 
+import json
 import os
 import uuid
 from datetime import datetime, date, timedelta, timezone
@@ -144,6 +145,35 @@ def register(app):
         meds = postgres.select("medications", where={"user_uuid": user_uuid}, order_by="name")
         return flask.jsonify(meds), 200
 
+    def _check_med_schedule_conflicts(user_uuid, new_times, new_days=None, exclude_med_id=None):
+        """Check if the proposed medication schedule conflicts with existing routines or medications.
+        Returns (has_conflict, conflict_message) tuple.
+        """
+        if not new_times:
+            return False, None
+
+        # Check conflicts with routines
+        user_routines = postgres.select("routines", {"user_uuid": user_uuid})
+        for r in user_routines:
+            sched = postgres.select_one("routine_schedules", {"routine_id": r["id"]})
+            if sched and sched.get("time") in new_times:
+                routine_days = json.loads(sched.get("days", "[]"))
+                if not new_days or any(d in routine_days for d in new_days):
+                    return True, f"Time conflicts with routine: {r.get('name', 'Unnamed routine')}"
+
+        # Check conflicts with other medications
+        user_meds = postgres.select("medications", {"user_uuid": user_uuid, "active": True})
+        for med in user_meds:
+            if med["id"] == exclude_med_id:
+                continue
+            med_times = med.get("times", [])
+            if isinstance(med_times, str):
+                med_times = json.loads(med_times)
+            if any(t in med_times for t in new_times):
+                return True, f"Time conflicts with medication: {med.get('name', 'Unnamed medication')}"
+
+        return False, None
+
     @app.route("/api/medications", methods=["POST"])
     def api_addMedication():
         """Add a medication. Body: {name, dosage, unit, frequency, times?, days_of_week?, interval_days?, start_date?, notes?}"""
@@ -158,6 +188,15 @@ def register(app):
         if missing:
             return flask.jsonify({"error": f"missing required fields: {', '.join(missing)}"}), 400
 
+        # Check for schedule conflicts
+        new_times = data.get("times", [])
+        new_days = data.get("days_of_week", [])
+        has_conflict, conflict_msg = _check_med_schedule_conflicts(
+            user_uuid, new_times, new_days
+        )
+        if has_conflict:
+            return flask.jsonify({"error": conflict_msg}), 409
+
         row = {
             "id": str(uuid.uuid4()),
             "user_uuid": user_uuid,
@@ -217,6 +256,17 @@ def register(app):
             "name", "dosage", "unit", "frequency", "times", "notes", "active",
             "days_of_week", "interval_days", "start_date", "next_dose_date",
         ]
+
+        # Check for schedule conflicts if times are being updated
+        if "times" in data:
+            new_times = data.get("times", [])
+            new_days = data.get("days_of_week") or existing.get("days_of_week", [])
+            has_conflict, conflict_msg = _check_med_schedule_conflicts(
+                user_uuid, new_times, new_days, exclude_med_id=med_id
+            )
+            if has_conflict:
+                return flask.jsonify({"error": conflict_msg}), 409
+
         updates = {k: v for k, v in data.items() if k in allowed}
         if not updates:
             return flask.jsonify({"error": "no valid fields to update"}), 400