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>

mail/server.py

@@ -8,10 +8,11 @@ import contextlib
 import imaplib
 import mailbox
 import gc
+import time
 import ctypes
 from email.header import decode_header
 from email.mime.text import MIMEText
-from email.utils import formatdate
+from email.utils import formatdate, parsedate_to_datetime
 from pathlib import Path
 from typing import Annotated
 
@@ -170,6 +171,32 @@ def _open_folder(acct_path, folder_name):
     return mailbox.Maildir(path, create=False) if os.path.isdir(path) else None
 
 
+MAX_SCAN = 2000  # Obergrenze gesammelter Treffer (Speicher-Schutz bei breiten Queries)
+DEADLINE_S = 120  # Wall-Clock-Limit: Server heilt sich selbst, nie wieder endloser Haenger
+
+
+def _iter_messages(md):
+    """Yield (key, msg); ueberspringt unparsbare Mails statt die Suche zu killen."""
+    try:
+        keys = list(md.keys())
+    except Exception:
+        return
+    for key in keys:
+        try:
+            msg = md.get_message(key)
+        except Exception:
+            continue
+        yield key, msg
+
+
+def _date_sortkey(date_str):
+    try:
+        dt = parsedate_to_datetime(date_str)
+        return dt.timestamp() if dt else 0.0
+    except Exception:
+        return 0.0
+
+
 @mcp.tool()
 def list_accounts() -> str:
     """List all email accounts with their folder count. Call this first to see available accounts."""
@@ -209,7 +236,9 @@ def search_mail(
     if not user:
         return "Error: not authenticated"
     query_lower = query.lower()
-    results = []
+    matches = []
+    truncated = False
+    t0 = time.monotonic()
     for acct_name, acct_path in _discover_accounts(user).items():
         if account and account not in acct_name:
             continue
@@ -219,21 +248,42 @@ def search_mail(
             md = _open_folder(acct_path, fld)
             if not md:
                 continue
-            for key, msg in md.items():
-                subj = _decode_hdr(msg.get("Subject", ""))
-                frm = _decode_hdr(msg.get("From", ""))
-                to = _decode_hdr(msg.get("To", ""))
-                date_str = msg.get("Date", "")
-                if query_lower not in f"{subj} {frm} {to}".lower():
-                    body = _get_body(msg)
-                    if query_lower not in body.lower():
-                        continue
-                results.append(f"[{date_str}] {frm} -> {to}\n  Subject: {subj}\n  Account: {acct_name}, Folder: {fld}, Key: {key}")
-                if len(results) >= limit:
-                    _trim_memory()
-                    return "\n\n".join(results)
+            for key, msg in _iter_messages(md):
+                try:
+                    subj = _decode_hdr(msg.get("Subject", ""))
+                    frm = _decode_hdr(msg.get("From", ""))
+                    to = _decode_hdr(msg.get("To", ""))
+                    date_str = msg.get("Date", "")
+                    if query_lower not in f"{subj} {frm} {to}".lower():
+                        if query_lower not in _get_body(msg).lower():
+                            continue
+                    matches.append((date_str, frm, to, subj, acct_name, fld, key))
+                except Exception:
+                    continue
+                if len(matches) >= MAX_SCAN:
+                    truncated = True
+                    break
+                if time.monotonic() - t0 > DEADLINE_S:
+                    truncated = True
+                    break
+            if truncated:
+                break
+        if truncated:
+            break
+    matches.sort(key=lambda m: _date_sortkey(m[0]), reverse=True)
+    shown = matches[:limit]
     _trim_memory()
-    return "\n\n".join(results) if results else "No results found"
+    if not shown:
+        return "No results found"
+    lines = [f"[{d}] {f} -> {t}\n  Subject: {s}\n  Account: {a}, Folder: {fl}, Key: {k}"
+             for (d, f, t, s, a, fl, k) in shown]
+    more = len(matches) - len(shown)
+    if more > 0:
+        if truncated:
+            lines.append(f"... mindestens {more} weitere Treffer (Scan-Limit erreicht; Suche eingrenzen).")
+        else:
+            lines.append(f"... {more} weitere Treffer (Suche eingrenzen oder limit erhoehen).")
+    return "\n\n".join(lines)
 
 
 @mcp.tool()