feat: Update session metrics handling for CSV-mapped values

- Enhanced the docstring for `upsert_session_metrics_from_csv_mapped` to clarify the handling of schema parameters and EAV logic.
- Modified the condition for skipping updates based on `source_field` to ensure only patchable columns are processed, improving data integrity during session metrics upsert operations.

backend/data_layer/activity_session_metrics.py

@@ -313,7 +313,17 @@ def upsert_session_metrics_from_csv_mapped(
     training_category: Optional[str],
     training_type_id: Optional[int],
 ) -> None:
-    """EAV nur für Schema-Parameter ohne source_field (reine Session-Metriken)."""
+    """
+    EAV für Schema-Parameter aus CSV-mapped Werten.
+
+    Spalten-gestützte Parameter (source_field ∈ ACTIVITY_LOG_PATCHABLE_COLUMNS) werden
+    ausschließlich über resolve_activity_log_column_patch_from_csv → activity_log
+    geschrieben — hier kein EAV.
+
+    Wenn source_field gesetzt ist, aber **kein** patchbarer Spaltenname (z. B. eigener
+    Key „stola“ wie der Parametername), wäre früher weder Spalten-Update noch EAV erfolgt;
+    dann EAV wie bei reinen Metriken.
+    """
     cur.execute(
         "SELECT profile_id FROM activity_log WHERE id = %s",
         (activity_log_id,),
@@ -330,7 +340,7 @@ def upsert_session_metrics_from_csv_mapped(
         if raw is None or raw == "":
             continue
         src_col = (spec.get("source_field") or "").strip()
-        if src_col:
+        if src_col and src_col in ACTIVITY_LOG_PATCHABLE_COLUMNS:
             continue
         tid = spec["training_parameter_id"]
         dt = spec["data_type"]

backend/migrations/056_activity_kcal_per_km_trigger_no_overwrite_on_update.sql

@@ -0,0 +1,35 @@
+-- Migration 056: kcal_per_km Trigger — manuelles Leeren bei UPDATE erlauben
+-- Problem: calculate_avg_hr_percent (014) setzte bei jedem UPDATE kcal_per_km aus
+-- kcal_active/distance_km, sobald beide gesetzt waren — ein bewusst geleertes Feld
+-- erschien sofort wieder.
+-- Lösung: automatische Ableitung nur noch bei INSERT (wenn kcal_per_km noch NULL ist).
+
+CREATE OR REPLACE FUNCTION calculate_avg_hr_percent()
+RETURNS TRIGGER AS $$
+DECLARE
+    user_max_hr INTEGER;
+BEGIN
+    SELECT hf_max INTO user_max_hr
+    FROM profiles
+    WHERE id = NEW.profile_id;
+
+    IF NEW.hr_avg IS NOT NULL AND user_max_hr IS NOT NULL AND user_max_hr > 0 THEN
+        NEW.avg_hr_percent := (NEW.hr_avg::float / user_max_hr::float) * 100;
+    END IF;
+
+    IF TG_OP = 'INSERT' THEN
+        IF NEW.kcal_active IS NOT NULL AND NEW.distance_km IS NOT NULL AND NEW.distance_km > 0 THEN
+            IF NEW.kcal_per_km IS NULL THEN
+                NEW.kcal_per_km := NEW.kcal_active::float / NEW.distance_km;
+            END IF;
+        END IF;
+    END IF;
+
+    RETURN NEW;
+END;
+$$ LANGUAGE plpgsql;
+
+DO $$
+BEGIN
+    RAISE NOTICE '✓ Migration 056: kcal_per_km nur noch bei INSERT auto-abgeleitet';
+END $$;