Bündel 2: Zentrale Helper für DRY-Cleanup, SW by-v1114

NEUE BACKEND-MODULE:

math_utils.py
- haversine_km(lat1, lon1, lat2, lon2) — Distanz in km
- haversine_m(...) — Convenience-Wrapper in Metern
- bbox_deg_from_km(lat, radius_km) — Bounding-Box-Approximation
  für SQL-Vorfilter (statt Haversine im Python-Loop)

config.py
- DB_PATH, MEDIA_DIR, BREEDER_DOCS_DIR, SCANINPUT_DIR
- API_TIMEOUT_SHORT (5s) / DEFAULT (10s) / LONG (30s)
- HTTP_USER_AGENT, HTTP_HEADERS

errors.py
- not_found(msg), forbidden(msg), bad_request(msg), unauthorized(msg)
- conflict(msg), too_many_requests(msg, retry_after), service_unavailable(msg)
- require_or_404(row, msg) — Convenience-Helper

UI.JS ERWEITERUNGEN:

UI.time erweitert:
- formatDate(d)     → "15.03.2026"
- formatDateTime(d) → "15.03.2026, 14:30"
- weekday(d)        → "Di"
- parseISO(str)     → {year, month, day}

UI.text (neu):
- truncate(str, maxLen, ellipsis='…')
- slug(str) — URL-Slug aus String (mit DE-Umlauten)

UI.money (neu):
- format(value) → "12,34 €" (de-DE, EUR)
- formatWithSuffix(value, '/Jahr')

HAVERSINE-MIGRATION (13 Backend-Routen):
alerts.py, services.py, places.py, events.py, diary.py, playdate.py,
lost.py, poison.py, adoption.py, gassi_zeiten.py, sitting.py, routen.py,
walks.py

- Alle lokalen def _haversine/haversine_km entfernt
- Aufrufe ersetzt durch haversine_km/haversine_m je nach Einheit
- from math_utils import haversine_km|haversine_m in jeder Datei

Tests 19/19 grün.

Hinweis: Migrationen für MEDIA_DIR (19 Stellen), API-Timeouts (12),
Date-Formatter im Frontend (24) und UI.text.truncate (5) sind als
Folge-Sprints möglich. Helper sind verfügbar.

backend/routes/diary.py

@@ -1,6 +1,6 @@
 """BAN YARO — Tagebuch Routes"""
 
-import os, uuid, json, math, logging, asyncio
+import os, uuid, json, logging, asyncio
 from fastapi import APIRouter, Depends, HTTPException, UploadFile, File
 from pydantic import BaseModel
 from typing import Optional
@@ -11,6 +11,7 @@ import httpx
 import weather as weather_mod
 from media_utils import convert_media, extract_video_thumb, safe_media_path, validate_upload, extract_gps_from_exif, generate_preview, preview_url_from, get_image_size
 from timeutils import safe_client_time
+from math_utils import haversine_km
 
 logger = logging.getLogger(__name__)
 
@@ -409,7 +410,7 @@ async def _fetch_pois_for_coords(lat: float, lon: float, limit: int = 5) -> list
                 elat = el.get("lat") or el.get("center", {}).get("lat")
                 elon = el.get("lon") or el.get("center", {}).get("lon")
                 if elat and elon:
-                    km = _haversine_km(lat, lon, elat, elon)
+                    km = haversine_km(lat, lon, elat, elon)
                     typ = next((el["tags"].get(k) for k in
                                 ["tourism", "historic", "leisure", "amenity", "shop"]
                                 if el["tags"].get(k)), "place")
@@ -422,16 +423,6 @@ async def _fetch_pois_for_coords(lat: float, lon: float, limit: int = 5) -> list
     return results[:limit]
 
 
-def _haversine_km(lat1, lon1, lat2, lon2) -> float:
-    R = 6371
-    dlat = math.radians(lat2 - lat1)
-    dlon = math.radians(lon2 - lon1)
-    a = (math.sin(dlat / 2) ** 2
-         + math.cos(math.radians(lat1)) * math.cos(math.radians(lat2))
-         * math.sin(dlon / 2) ** 2)
-    return R * 2 * math.asin(math.sqrt(a))
-
-
 @router.get("/{dog_id}/diary/nearby")
 async def nearby_places(dog_id: int, lat: float, lon: float,
                         user=Depends(get_current_user)):
@@ -445,7 +436,7 @@ async def nearby_places(dog_id: int, lat: float, lon: float,
             (user["id"],)
         ).fetchall()
         for p in places:
-            km = _haversine_km(lat, lon, p["lat"], p["lon"])
+            km = haversine_km(lat, lon, p["lat"], p["lon"])
             if km <= 5:
                 results.append({"name": p["name"], "type": p["typ"] or "place",
                                  "lat": p["lat"], "lon": p["lon"],
@@ -456,7 +447,7 @@ async def nearby_places(dog_id: int, lat: float, lon: float,
             "SELECT name, type, lat, lon FROM osm_pois WHERE name IS NOT NULL AND name != ''"
         ).fetchall()
         for p in osm:
-            km = _haversine_km(lat, lon, p["lat"], p["lon"])
+            km = haversine_km(lat, lon, p["lat"], p["lon"])
             if km <= 2:
                 results.append({"name": p["name"], "type": p["type"],
                                  "lat": p["lat"], "lon": p["lon"],
@@ -503,7 +494,7 @@ async def nearby_places(dog_id: int, lat: float, lon: float,
                     elat = el.get("lat") or el.get("center", {}).get("lat")
                     elon = el.get("lon") or el.get("center", {}).get("lon")
                     if elat and elon:
-                        km = _haversine_km(lat, lon, elat, elon)
+                        km = haversine_km(lat, lon, elat, elon)
                         typ = next((el["tags"].get(k) for k in
                                     ["tourism","historic","leisure","amenity","shop"]
                                     if el["tags"].get(k)), "place")