perf: use imap_tools uid_list fetch to skip manual UID batching

imap_tools 1.14.0 adds a uid_list fetch arg that fetches by UID
directly without issuing a SEARCH command, and does its own
bulk-fetch batching. Use it in place of the manual per-batch
AND(uid=...) fetch loop.

pyproject.toml

@@ -47,7 +47,7 @@ dependencies = [
   "gotenberg-client~=0.14.0",
   "httpx-oauth~=0.16",
   "ijson>=3.2",
-  "imap-tools~=1.13.0",
+  "imap-tools~=1.14.0",
   "jinja2~=3.1.5",
   "langdetect~=1.0.9",
   "llama-index-core>=0.14.22",