safe_float/safe_int Hilfsfunktionen: doppelten try/except-Code konsolidiert

export_csv.py und export_sivas.py enthielten je ca. 10 nahezu identische
try/except (ValueError, TypeError)-Bloecke fuer "String zu float/int mit
Fallback". Neue gemeinsame Helfer safe_float()/safe_int()
(export_blockpatterns.py) ersetzen diese Bloecke; dabei auch zwei bislang
ungeschuetzte int()/float()-Aufrufe in export_sivas.py (Kreisel-Zaehler)
abgesichert, die bei fehlerhaften Attributwerten sonst abgestuerzt waeren.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

lib/export_csv.py

@@ -41,7 +41,7 @@ import json
 import sys
 import os
 
-from export_blockpatterns import load_patterns, matches_any, csv_quote
+from export_blockpatterns import load_patterns, matches_any, csv_quote, safe_float
 from export_planquadrat import load_planquadrat_config, resolve_origins, compute_planquadrat
 from export_neighbors import (
     load_neighbor_tolerance_mm,
@@ -108,12 +108,9 @@ def get_drehung(block):
     """Liest DREHUNG aus Block-Attributen. Fallback: CAD-Rotation."""
     attribs = block.get("attribs", {})
     drehung_raw = attribs.get("DREHUNG")
-    if drehung_raw is not None:
-        try:
-            return float(drehung_raw)
-        except (ValueError, TypeError):
-            pass
-    return block.get("rotation", 0.0)
+    if drehung_raw is None:
+        return block.get("rotation", 0.0)
+    return safe_float(drehung_raw, block.get("rotation", 0.0))
 
 
 def build_bogen_merkmale(block, eintrag):
@@ -162,10 +159,7 @@ def get_laenge_mm(block):
     """Liest LAENGE (oder A) aus Block-Attributen. Fallback: 2000mm."""
     attribs = block.get("attribs", {})
     laenge = attribs.get("LAENGE") or attribs.get("A")
-    try:
-        return float(laenge)
-    except (TypeError, ValueError):
-        return 2000.0
+    return safe_float(laenge, 2000.0)
 
 
 def build_gerade_merkmale(block):
@@ -228,16 +222,8 @@ def build_omni_sum_merkmale(cnt_boegen, cnt_wk, cnt_einzel, cnt_delta, cnt_doppe
 
 def build_kreisel_merkmale(block):
     attribs = block.get("attribs", {})
-    abstand_mm = attribs.get("ABSTAND", "2300")
-    try:
-        abstand_m = str(round(float(abstand_mm) / 1000.0, 2))
-    except (ValueError, TypeError):
-        abstand_m = "2.3"
-    hoehe_mm = attribs.get("HOEHE", "0")
-    try:
-        hoehe_m = str(round(float(hoehe_mm) / 1000.0, 2))
-    except (ValueError, TypeError):
-        hoehe_m = "0"
+    abstand_m = str(round(safe_float(attribs.get("ABSTAND", "2300"), 2300.0) / 1000.0, 2))
+    hoehe_m = str(round(safe_float(attribs.get("HOEHE", "0"), 0.0) / 1000.0, 2))
     return {
         "Abstand (Kreiselachse A - Kreiselachse) in Meter": abstand_m,
         "Anzahl der Separatoren": attribs.get("ANZAHL_SEPARATOR", attribs.get("N_SEPARATOREN", "2")),