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>

contacts/server.py

@@ -4,6 +4,7 @@ import os, sys, re, contextlib, uuid, base64
 from typing import Annotated
 
 import httpx, vobject
+import time
 from pydantic import Field
 from mcp.server.fastmcp import FastMCP
 from mcp.types import TextContent, ImageContent
@@ -38,11 +39,15 @@ def _discover_ab(user):
             books.append({"name": nm.group(1) if nm else href.split("/")[-2], "href": href})
     return books
 
-def _get_contacts(href, auth):
+PARSE_DEADLINE_S = 12   # Wall-Clock-Limit fuer client-seitiges vobject-Parsen
+
+
+def _get_contacts(href, auth, t0=None):
     body = '<?xml version="1.0"?><c:addressbook-query xmlns:d="DAV:" xmlns:c="urn:ietf:params:xml:ns:carddav"><d:prop><d:getetag/><c:address-data/></d:prop></c:addressbook-query>'
     r = httpx.request("REPORT", RADICALE + href, content=body, auth=auth, headers={"Depth": "1", "Content-Type": "application/xml"}, timeout=60)
     contacts = []
     for m in re.finditer(r'<(?:c|CR):address-data[^>]*>(.*?)</(?:c|CR):address-data>', r.text, re.DOTALL):
+        if t0 is not None and (time.monotonic() - t0) > PARSE_DEADLINE_S: break
         raw = m.group(1).replace("&lt;","<").replace("&gt;",">").replace("&amp;","&")
         try: contacts.append(vobject.readOne(raw))
         except: pass
@@ -98,14 +103,22 @@ def search_contacts(
     user = get_current_user()
     if not user: return "Error: not authenticated"
     q = query.lower()
+    t0 = time.monotonic()
     results = []
+    truncated = False
     for book in _discover_ab(user):
-        for c in _get_contacts(book["href"], _auth(user)):
+        for c in _get_contacts(book["href"], _auth(user), t0=t0):
             txt = " ".join(str(getattr(c, a, None) or '') for a in ['fn','email','tel','org','note','nickname']).lower()
             if q in txt:
                 results.append(_brief(c))
                 if len(results) >= limit: break
-    return "\n\n".join(results) if results else "Keine Kontakte gefunden"
+        if len(results) >= limit: break
+        if (time.monotonic() - t0) > PARSE_DEADLINE_S:
+            truncated = True; break
+    out = "\n\n".join(results) if results else "Keine Kontakte gefunden"
+    if truncated:
+        out += "\n\n[Suche zeitbegrenzt — Begriff praezisieren]"
+    return out
 
 
 def _get_photo_data(card):