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/testdata/gen_maildir.py

@@ -46,6 +46,33 @@ add("mcp-test-mail","INBOX", mail_with("voice@example.com","Sprachnachricht","Ku
 add("mcp-test-mail","INBOX", mail_with("projekt@example.com","Projektdateien","Archiv und Notizen.",["archive.zip","notes.txt","data.csv"]))
 add("mcp-test-mail","INBOX", mail_with("media@example.com","Praesentation + Clip","Folien und ein kurzes Video.",["slides.pptx","clip.mp4"]))
 
+# --- Edge-Cases: Robustheit + uralte Mails (Fix 2026-06-24) ---
+def addraw(acct, folder, raw_bytes):
+    path=os.path.join(BASE,acct,folder); os.makedirs(os.path.dirname(path),exist_ok=True)
+    mailbox.Maildir(path,create=True).add(raw_bytes)
+
+# Uralte Mail (2009) mit eindeutigem Token -> Suche muss alte Mails finden
+_old=simple("archiv@example.com","mcptest@local","Uralte Rechnung URALTMAIL2009","Sehr alte Mail aus 2009 zum Testen der Alt-Mail-Suche.")
+_old.replace_header("Date","Tue, 03 Mar 2009 08:15:00 +0100")
+add("mcp-test-mail","Archive",_old)
+
+# Mail mit kaputtem Charset x-unknown -> darf die Suche NICHT killen, Token findbar
+addraw("mcp-test-mail","INBOX",
+ b"From: weird@example.com\r\nTo: mcptest@local\r\n"
+ b"Subject: Kaputtes Encoding XUNKNOWNTOKEN\r\n"
+ b"Date: Wed, 10 Jan 2018 12:00:00 +0100\r\n"
+ b'Content-Type: text/plain; charset="x-unknown"\r\n'
+ b"Content-Transfer-Encoding: 8bit\r\n\r\n"
+ b"Koerpertext mit kaputtem Charset XUNKNOWNTOKEN und Umlaut \xfc.\r\n")
+
+# Mail mit kaputtem encoded-word-Header -> decode_hdr darf nicht crashen
+addraw("mcp-test-mail","INBOX",
+ b"From: =?invalid-charset?Q?Br=F6tchen?= <bad@example.com>\r\nTo: mcptest@local\r\n"
+ b"Subject: =?x-unknown?B?a2FwdXR0?= BADHEADERTOKEN\r\n"
+ b"Date: Fri, 05 Jul 2013 09:00:00 +0200\r\n"
+ b"Content-Type: text/plain; charset=utf-8\r\n\r\n"
+ b"Body BADHEADERTOKEN.\r\n")
+
 # new -> cur
 for r,d,f in os.walk(BASE):
     if r.endswith("new"):

tests/testdata/maildir/mcp-test-mail/Archive/cur/1782276881.M377400P929578Q10.polo:2,S

@@ -0,0 +1,9 @@
+Content-Type: text/plain; charset="utf-8"
+MIME-Version: 1.0
+Content-Transfer-Encoding: base64
+From: archiv@example.com
+To: mcptest@local
+Subject: Uralte Rechnung URALTMAIL2009
+Date: Tue, 03 Mar 2009 08:15:00 +0100
+
+U2VociBhbHRlIE1haWwgYXVzIDIwMDkgenVtIFRlc3RlbiBkZXIgQWx0LU1haWwtU3VjaGUu

tests/testdata/maildir/mcp-test-mail/INBOX/cur/1782276881.M350723P929578Q4.polo:2,S

@@ -1,11 +1,11 @@
-Content-Type: multipart/mixed; boundary="===============3363393740883118962=="
+Content-Type: multipart/mixed; boundary="===============2801843982600110124=="
 MIME-Version: 1.0
 From: billing@example.com
 To: mcptest@local
 Subject: Ihre Rechnung Juni 2026
 Date: Tue, 17 Jun 2026 10:00:00 +0200
 
---===============3363393740883118962==
+--===============2801843982600110124==
 Content-Type: text/plain; charset="utf-8"
 MIME-Version: 1.0
 Content-Transfer-Encoding: base64
@@ -13,7 +13,7 @@ Content-Transfer-Encoding: base64
 SW0gQW5oYW5nIGRpZSBSZWNobnVuZyAoVGV4dC1QREYpIHVuZCBkZXIgU2NhbiAoQmlsZC1QREYp
 Lg==
 
---===============3363393740883118962==
+--===============2801843982600110124==
 Content-Type: application/octet-stream
 MIME-Version: 1.0
 Content-Transfer-Encoding: base64
@@ -40,7 +40,7 @@ b290IDIgMCBSCi9JbmZvIDcgMCBSCi9JRCBbPDkzRTNFOTU5Q0U4RUI1RUZFRkRFMjQyNjRCQkIy
 NzIxPjw5M0UzRTk1OUNFOEVCNUVGRUZERTI0MjY0QkJCMjcyMT5dCj4+CnN0YXJ0eHJlZgo3NzkK
 JSVFT0YK
 
---===============3363393740883118962==
+--===============2801843982600110124==
 Content-Type: application/octet-stream
 MIME-Version: 1.0
 Content-Transfer-Encoding: base64
@@ -217,4 +217,4 @@ MDAwMCBuIAowMDAwMDA4NzI4IDAwMDAwIG4gCjAwMDAwMDg3NDcgMDAwMDAgbiAKMDAwMDAwODc2
 OSAwMDAwMCBuIAowMDAwMDA4Nzg4IDAwMDAwIG4gCnRyYWlsZXIKPDwKL1NpemUgMTgKL0luZm8g
 MTcgMCBSCi9Sb290IDEgMCBSCj4+CnN0YXJ0eHJlZgo5MjM3CiUlRU9GCg==
 
---===============3363393740883118962==--
+--===============2801843982600110124==--

tests/testdata/maildir/mcp-test-mail/INBOX/cur/1782276881.M355288P929578Q5.polo:2,S

@@ -1,18 +1,18 @@
-Content-Type: multipart/mixed; boundary="===============4945638286946888290=="
+Content-Type: multipart/mixed; boundary="===============1039225266335026552=="
 MIME-Version: 1.0
 From: foto@example.com
 To: mcptest@local
 Subject: Fotos vom Wochenende
 Date: Tue, 17 Jun 2026 10:00:00 +0200
 
---===============4945638286946888290==
+--===============1039225266335026552==
 Content-Type: text/plain; charset="utf-8"
 MIME-Version: 1.0
 Content-Transfer-Encoding: base64
 
 QW5iZWkgendlaSBCaWxkZXIu
 
---===============4945638286946888290==
+--===============1039225266335026552==
 Content-Type: application/octet-stream
 MIME-Version: 1.0
 Content-Transfer-Encoding: base64
@@ -194,7 +194,7 @@ AKKKKACiiigAooooAKKKKACiiigAooooAKKKKACiiigAooooAKKKKACiiigAooooAKKKKACiiigA
 ooooAKKKKACiiigAooooAKKKKACiiigAooooAKKKKACiiigAooooAKKKKACiiigAooooAKKKKACi
 iigAooooAKKKKACiiigAooooAKKKKACiiigAooooAKKKKAP/2Q==
 
---===============4945638286946888290==
+--===============1039225266335026552==
 Content-Type: application/octet-stream
 MIME-Version: 1.0
 Content-Transfer-Encoding: base64
@@ -262,4 +262,4 @@ ABAgwAAQ0O1ULfTCQ1NP1VIA8P+eHTAABAgwAAQIMAAEfKjvgKc8suBU3QcAnFXsgAEgQIABIECA
 ASBAgAEgQIABIECAASBAgAEgQIABIECAASBAgAEgQIABIECAASBAgAEgQIABIECAASBAgAEgQIAB
 IECAASDgfwAcngvShI2jGAAAAABJRU5ErkJggg==
 
---===============4945638286946888290==--
+--===============1039225266335026552==--

tests/testdata/maildir/mcp-test-mail/INBOX/cur/1782276881.M362041P929578Q6.polo:2,S

@@ -1,18 +1,18 @@
-Content-Type: multipart/mixed; boundary="===============8126427565043495650=="
+Content-Type: multipart/mixed; boundary="===============3148390453173742087=="
 MIME-Version: 1.0
 From: buero@example.com
 To: mcptest@local
 Subject: Quartalsbericht Q2
 Date: Tue, 17 Jun 2026 10:00:00 +0200
 
---===============8126427565043495650==
+--===============3148390453173742087==
 Content-Type: text/plain; charset="utf-8"
 MIME-Version: 1.0
 Content-Transfer-Encoding: base64
 
 QmVyaWNodCAoV29yZCkgdW5kIFphaGxlbiAoRXhjZWwpIGFuYmVpLg==
 
---===============8126427565043495650==
+--===============3148390453173742087==
 Content-Type: application/octet-stream
 MIME-Version: 1.0
 Content-Transfer-Encoding: base64
@@ -663,7 +663,7 @@ AIkVAAASAAAAAAAAAAAAAACAATmBAAB3b3JkL251bWJlcmluZy54bWxQSwECFAMUAAAACABvPtNc
 osjWZ70FAACEIAAAFwAAAAAAAAAAAAAAgAHUhAAAZG9jUHJvcHMvdGh1bWJuYWlsLmpwZWdQSwUG
 AAAAABEAEQBhBAAAxooAAAAA
 
---===============8126427565043495650==
+--===============3148390453173742087==
 Content-Type: application/octet-stream
 MIME-Version: 1.0
 Content-Transfer-Encoding: base64
@@ -756,4 +756,4 @@ AxQAAAAIAG8+01wkHpuirQAAAPgBAAAaAAAAAAAAAAAAAACAAZIOAAB4bC9fcmVscy93b3JrYm9v
 ay54bWwucmVsc1BLAQIUAxQAAAAIAG8+01xlkHmSGQEAAM8DAAATAAAAAAAAAAAAAACAAXcPAABb
 Q29udGVudF9UeXBlc10ueG1sUEsFBgAAAAAJAAkAPgIAAMEQAAAAAA==
 
---===============8126427565043495650==--
+--===============3148390453173742087==--

tests/testdata/maildir/mcp-test-mail/INBOX/cur/1782276881.M366317P929578Q7.polo:2,S

@@ -1,18 +1,18 @@
-Content-Type: multipart/mixed; boundary="===============5981132086698869830=="
+Content-Type: multipart/mixed; boundary="===============2935331032460717163=="
 MIME-Version: 1.0
 From: voice@example.com
 To: mcptest@local
 Subject: Sprachnachricht
 Date: Tue, 17 Jun 2026 10:00:00 +0200
 
---===============5981132086698869830==
+--===============2935331032460717163==
 Content-Type: text/plain; charset="utf-8"
 MIME-Version: 1.0
 Content-Transfer-Encoding: base64
 
 S3VyemUgQXVkaW9uYWNocmljaHQgaW0gQW5oYW5nLg==
 
---===============5981132086698869830==
+--===============2935331032460717163==
 Content-Type: application/octet-stream
 MIME-Version: 1.0
 Content-Transfer-Encoding: base64
@@ -175,4 +175,4 @@ VVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVX/+xDE94AJeGVd+akgAAAANIOAAARV
 VVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVV
 VVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVQ==
 
---===============5981132086698869830==--
+--===============2935331032460717163==--

tests/testdata/maildir/mcp-test-mail/INBOX/cur/1782276881.M369074P929578Q8.polo:2,S

@@ -1,18 +1,18 @@
-Content-Type: multipart/mixed; boundary="===============1387712317359960679=="
+Content-Type: multipart/mixed; boundary="===============0315165645846539514=="
 MIME-Version: 1.0
 From: projekt@example.com
 To: mcptest@local
 Subject: Projektdateien
 Date: Tue, 17 Jun 2026 10:00:00 +0200
 
---===============1387712317359960679==
+--===============0315165645846539514==
 Content-Type: text/plain; charset="utf-8"
 MIME-Version: 1.0
 Content-Transfer-Encoding: base64
 
 QXJjaGl2IHVuZCBOb3RpemVuLg==
 
---===============1387712317359960679==
+--===============0315165645846539514==
 Content-Type: application/octet-stream
 MIME-Version: 1.0
 Content-Transfer-Encoding: base64
@@ -24,7 +24,7 @@ ZGF0YS5jc3ZuYW1lLHdlcnQKQWxwaGEsMQpCZXRhLDIKUEsBAhQDFAAAAAAAbz7TXE28oLEtAAAA
 LQAAAAkAAAAAAAAAAAAAALCBAAAAAG5vdGVzLnR4dFBLAQIUAxQAAAAAAG8+01wa5IaIGQAAABkA
 AAAIAAAAAAAAAAAAAACwgVQAAABkYXRhLmNzdlBLBQYAAAAAAgACAG0AAACTAAAAAAA=
 
---===============1387712317359960679==
+--===============0315165645846539514==
 Content-Type: application/octet-stream
 MIME-Version: 1.0
 Content-Transfer-Encoding: base64
@@ -32,7 +32,7 @@ Content-Disposition: attachment; filename="notes.txt"
 
 RWluZmFjaGUgVGV4dGRhdGVpLgpaZWlsZSAyLgpVbWxhdXRlOiBhZW9ldWUK
 
---===============1387712317359960679==
+--===============0315165645846539514==
 Content-Type: application/octet-stream
 MIME-Version: 1.0
 Content-Transfer-Encoding: base64
@@ -40,4 +40,4 @@ Content-Disposition: attachment; filename="data.csv"
 
 bmFtZSx3ZXJ0CkFscGhhLDEKQmV0YSwyCg==
 
---===============1387712317359960679==--
+--===============0315165645846539514==--

tests/testdata/maildir/mcp-test-mail/INBOX/cur/1782276881.M374012P929578Q9.polo:2,S

@@ -1,18 +1,18 @@
-Content-Type: multipart/mixed; boundary="===============0497362329568289493=="
+Content-Type: multipart/mixed; boundary="===============4194720031885655663=="
 MIME-Version: 1.0
 From: media@example.com
 To: mcptest@local
 Subject: Praesentation + Clip
 Date: Tue, 17 Jun 2026 10:00:00 +0200
 
---===============0497362329568289493==
+--===============4194720031885655663==
 Content-Type: text/plain; charset="utf-8"
 MIME-Version: 1.0
 Content-Transfer-Encoding: base64
 
 Rm9saWVuIHVuZCBlaW4ga3VyemVzIFZpZGVvLg==
 
---===============0497362329568289493==
+--===============4194720031885655663==
 Content-Type: application/octet-stream
 MIME-Version: 1.0
 Content-Transfer-Encoding: base64
@@ -515,7 +515,7 @@ AAAANgEAACAAAAAAAAAAAAAAAIAB01sAAHBwdC9zbGlkZXMvX3JlbHMvc2xpZGUxLnhtbC5yZWxz
 UEsBAhQDFAAAAAgAbz7TXFqgDq2jBQAA4w8AABcAAAAAAAAAAAAAAIAByFwAAGRvY1Byb3BzL3Ro
 dW1ibmFpbC5qcGVnUEsFBgAAAAAmACYAowsAAKBiAAAAAA==
 
---===============0497362329568289493==
+--===============4194720031885655663==
 Content-Type: application/octet-stream
 MIME-Version: 1.0
 Content-Transfer-Encoding: base64
@@ -713,4 +713,4 @@ AX0AAAHtAAABgwAAAukAAADGAAAAUQAAAEYAAAJOAAAAvgAAAGYAAABfAAAAFHN0Y28AAAAAAAAA
 AQAAADAAAABhdWR0YQAAAFltZXRhAAAAAAAAACFoZGxyAAAAAAAAAABtZGlyYXBwbAAAAAAAAAAA
 AAAAACxpbHN0AAAAJKl0b28AAAAcZGF0YQAAAAEAAAAATGF2ZjYyLjMuMTAw
 
---===============0497362329568289493==--
+--===============4194720031885655663==--

tests/testdata/maildir/mcp-test-mail/INBOX/cur/1782276881.M378820P929578Q11.polo:2,S

@@ -0,0 +1,8 @@
+From: weird@example.com
+To: mcptest@local
+Subject: Kaputtes Encoding XUNKNOWNTOKEN
+Date: Wed, 10 Jan 2018 12:00:00 +0100
+Content-Type: text/plain; charset="x-unknown"
+Content-Transfer-Encoding: 8bit
+
+Koerpertext mit kaputtem Charset XUNKNOWNTOKEN und Umlaut ü.

tests/testdata/maildir/mcp-test-mail/INBOX/cur/1782276881.M379851P929578Q12.polo:2,S

@@ -0,0 +1,7 @@
+From: =?invalid-charset?Q?Br=F6tchen?= <bad@example.com>
+To: mcptest@local
+Subject: =?x-unknown?B?a2FwdXR0?= BADHEADERTOKEN
+Date: Fri, 05 Jul 2013 09:00:00 +0200
+Content-Type: text/plain; charset=utf-8
+
+Body BADHEADERTOKEN.