harden: per-item robustness + deadlines/caps across connectors; layered tests

Mail: _safe_decode + _iter_messages (per-mail try/except) -> eine kaputte Mail
(charset x-unknown) bricht die Suche nicht mehr ab, findet so auch uralte Mails.
Vollscan + Datum-Sort + MAX_SCAN/DEADLINE_S (Selbstheilung, kein 24h-Haenger mehr).

Files: search_files mit SEARCH_DEADLINE_S + SEARCH_MAX_DIRS begrenzt (war
unbegrenzte rekursive PROPFIND -> real 35s/449 Calls).

Calendar/Contacts: PARSE_DEADLINE_S fuer client-seitiges vobject-Parsen;
MAX_RESULTS-Output-Cap in get_events/get_tasks (war 10939 Zeilen bei 6000 Events);
search Top-N + Hinweise.

Tests: in Schichten getrennt -> Smoke (nightly), Edge + Stress (on-demand).
Neu: test_smoke/test_edge/test_stress + conftest-Marker + run_full_tests.sh,
nightly laeuft nur Smoke. Kontakt-Foto-Roundtrip-Test, Mail-Edge-Mails
(x-unknown, kaputter Header, 2009er Alt-Mail).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

tests/run_full_tests.sh

@@ -0,0 +1,28 @@
+#!/bin/bash
+# MCP Voll-Tests — ON-DEMAND (NICHT naechtlich; manuell ausfuehren).
+# Funktional (test_all.py) + Edge-Cases (test_edge.py) + Stress/Concurrency (test_stress.py).
+# Schreibt Testdaten in die mcptest-Sandbox (calendar-test, contacts-test, /.mcp-tests*, Inbox).
+#
+# Nutzung:
+#   /opt/mcp-servers/tests/run_full_tests.sh            # alles
+#   /opt/mcp-servers/tests/run_full_tests.sh -m stress  # nur eine Schicht (pytest-Marker)
+set -uo pipefail
+
+LOG="/var/log/mcp-tests-full.log"
+VENV="/opt/mcp-servers/venv/bin"
+cd /opt/mcp-servers/tests || exit 1
+
+echo "[$(date)] MCP Voll-Tests gestartet" | tee -a "$LOG"
+
+if [ "$#" -gt 0 ]; then
+    # z.B. -m smoke | -m edge | -m stress  (Marker-basiert ueber alle Dateien)
+    OUTPUT=$($VENV/python -m pytest test_all.py test_edge.py test_stress.py "$@" -v --tb=short 2>&1)
+else
+    OUTPUT=$($VENV/python -m pytest test_all.py test_edge.py test_stress.py -v --tb=short 2>&1)
+fi
+EXIT=$?
+
+echo "$OUTPUT" | tee -a "$LOG"
+echo "$OUTPUT" | tail -1
+echo "[$(date)] MCP Voll-Tests fertig (exit $EXIT)" | tee -a "$LOG"
+exit $EXIT