fix(projekt-matching): break infinite alert loop (issue 2)

Root cause chain (evidence: 25+ failed traces on nproj/3022414):
straight quote in page text ends the guided-decoding JSON string
early -> grammar deadlock -> whitespace loop until context/token
limit -> chat_json fails 3x (~35 min) -> IMAP conn idles out ->
move_to_trash raises -> mail never trashed -> reprocessed forever.

- ingest/mailer: MailBox.ensure_alive() reconnect before finalize;
  move_to_trash failure falls back to flag_checked, run continues
- stages: page_text() feeds only div.content minus skill-tag cloud
  to the LLM and maps quote chars to apostrophes (the actual
  degeneration trigger, live-verified: extract now OK in 21 s)
- llm: requirements maxItems 40; max_tokens 8192 caps degenerate
  runs at ~100 s instead of ~10 min

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

projekt-matching/projektmatch/mailer.py

@@ -16,12 +16,31 @@ KEYWORD = "$ProjektChecked"
 
 class MailBox:
     def __init__(self, user, password, conn=None):
-        self.conn = conn or imaplib.IMAP4_SSL(IMAP_HOST, IMAP_PORT)
-        if conn is None:
-            self.conn.login(user, password)
+        self.user, self.password = user, password
+        self.conn = conn or self._connect()
         self.conn.select("INBOX")
         self._trash = None
 
+    def _connect(self):
+        conn = imaplib.IMAP4_SSL(IMAP_HOST, IMAP_PORT)
+        conn.login(self.user, self.password)
+        return conn
+
+    def ensure_alive(self):
+        """Reconnect if the server dropped the connection (idle timeout)."""
+        try:
+            typ, _ = self.conn.noop()
+            if typ == "OK":
+                return
+        except Exception:      # noqa: BLE001
+            pass
+        try:
+            self.conn.logout()
+        except Exception:      # noqa: BLE001
+            pass
+        self.conn = self._connect()
+        self.conn.select("INBOX")
+
     def unchecked_uids(self):
         typ, data = self.conn.uid("SEARCH", None, f"UNKEYWORD {KEYWORD}")
         if typ != "OK" or not data or not data[0]: