Phase 2 Health-Check tenant-fähig + Historie

- migrations/2026-05-09d_source_health_history.py NEU: source_health_history-Tabelle
  (Append-only Verlauf der Health-Check-Runs mit run_id und archived_at)
- shared/services/source_health.py:
  - tenant_id IS NULL Filter raus -> auch Tenant-Quellen werden gecheckt
  - Mojibake (Triple-Encoded UTF-8) via ftfy gefixt
  - DELETE FROM source_health_checks: vorher Stand mit run_id (uuid4) in
    source_health_history archivieren -> kein Datenverlust mehr
  - User-Agent + Timeout aus config.HEALTH_CHECK_* statt hardcoded
- routers/sources.py /health/run-stream: gleiche Änderungen wie oben
- config.py: HEALTH_CHECK_USER_AGENT + HEALTH_CHECK_TIMEOUT_S ergänzt

src/routers/sources.py

@@ -1,5 +1,6 @@
 """Grundquellen-Verwaltung und Kundenquellen-Übersicht."""
 import logging
+import uuid
 
 from fastapi import APIRouter, Depends, HTTPException, status, Request
 from fastapi.responses import StreamingResponse
@@ -10,6 +11,7 @@ import aiosqlite
 from auth import get_current_admin
 from database import db_dependency
 from audit import log_action, get_client_ip, row_to_dict
+from config import HEALTH_CHECK_USER_AGENT, HEALTH_CHECK_TIMEOUT_S
 from shared.source_rules import (
     discover_source,
     discover_all_feeds,
@@ -564,7 +566,7 @@ async def run_health_check_stream(
     # Quellen laden
     cursor = await db.execute(
         "SELECT id, name, url, domain, source_type, article_count, last_seen_at "
-        "FROM sources WHERE status = 'active' AND tenant_id IS NULL"
+        "FROM sources WHERE status = 'active'"  # tenant + global
     )
     sources = [dict(row) for row in await cursor.fetchall()]
     sources_with_url = [s for s in sources if s["url"]]
@@ -577,6 +579,15 @@ async def run_health_check_stream(
         # Phase 1: Erreichbarkeit
         yield f"data: {_json.dumps({'phase': 'check', 'checked': 0, 'total': total, 'current': ''})}\n\n"
 
+        # Bisherigen Stand archivieren, dann frisch
+        run_id = uuid.uuid4().hex[:12]
+        await db.execute(
+            "INSERT INTO source_health_history "
+            "(run_id, source_id, check_type, status, message, details, checked_at) "
+            "SELECT ?, source_id, check_type, status, message, details, checked_at "
+            "FROM source_health_checks",
+            (run_id,),
+        )
         await db.execute("DELETE FROM source_health_checks")
         await db.commit()
 
@@ -584,8 +595,8 @@ async def run_health_check_stream(
         checked = 0
 
         async with httpx.AsyncClient(
-            timeout=15.0, follow_redirects=True,
-            headers={"User-Agent": "Mozilla/5.0 (compatible; OSINT-Monitor/1.0)"},
+            timeout=HEALTH_CHECK_TIMEOUT_S, follow_redirects=True,
+            headers={"User-Agent": HEALTH_CHECK_USER_AGENT},
         ) as client:
             for source in sources_with_url:
                 try: