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

migrations/2026-05-09d_source_health_history.py

@@ -0,0 +1,57 @@
+"""Migration 2026-05-09d: source_health_history (Verlauf der Health-Checks).
+
+Bislang wurde vor jedem Health-Check-Run die Tabelle source_health_checks geleert
+(DELETE FROM source_health_checks). Damit ging die Historie verloren - kein
+Trend, keine Vergleichsmöglichkeit über Runs.
+
+Diese Migration legt eine reine Append-Tabelle source_health_history an.
+Vor jedem Health-Check-Run wird der aktuelle Stand von source_health_checks
+hier archiviert (mit run_id und archived_at).
+
+Ausführung:
+    DB_PATH=/home/claude-dev/osint-data/osint.db python3 migrations/2026-05-09d_source_health_history.py
+    DB_PATH=/home/claude-dev/AegisSight-Monitor-staging/data/osint.db python3 migrations/2026-05-09d_source_health_history.py
+"""
+import os
+import sqlite3
+import sys
+
+
+def main(db_path: str) -> int:
+    if not os.path.exists(db_path):
+        print(f"FEHLER: DB nicht gefunden: {db_path}", file=sys.stderr)
+        return 1
+
+    conn = sqlite3.connect(db_path, timeout=60)
+    conn.execute("PRAGMA busy_timeout = 60000")
+    conn.execute("PRAGMA journal_mode = WAL")
+
+    print(f"Migration auf {db_path}")
+
+    conn.executescript("""
+    CREATE TABLE IF NOT EXISTS source_health_history (
+        id INTEGER PRIMARY KEY AUTOINCREMENT,
+        run_id TEXT NOT NULL,
+        source_id INTEGER NOT NULL,
+        check_type TEXT NOT NULL,
+        status TEXT NOT NULL,
+        message TEXT,
+        details TEXT,
+        checked_at TIMESTAMP,
+        archived_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
+    );
+    CREATE INDEX IF NOT EXISTS idx_source_health_history_run ON source_health_history(run_id);
+    CREATE INDEX IF NOT EXISTS idx_source_health_history_source ON source_health_history(source_id, archived_at DESC);
+    CREATE INDEX IF NOT EXISTS idx_source_health_history_status ON source_health_history(status, archived_at DESC);
+    """)
+    print("  + source_health_history + Indizes (idempotent)")
+
+    conn.commit()
+    conn.close()
+    print("Migration abgeschlossen.")
+    return 0
+
+
+if __name__ == "__main__":
+    db_path = os.environ.get("DB_PATH", "/home/claude-dev/osint-data/osint.db")
+    sys.exit(main(db_path))