v1.4.0: storage provider parity — attachments, outbound recording, search fix

sqlite & db9: upgrade schema with attachments table and metadata columns
(has_attachments, attachment_count, attachment_names, attachment_search_text,
message_id). saveEmail() now persists attachment records. getEmail() returns
attachment metadata. getAttachment() serves text-extractable attachments.

send(): record outbound emails in local storage (sqlite/db9) after
successful send. Best-effort, skipped for remote provider.

sqlite: fix LIKE wildcard injection — escape % and _ in search queries.

types: add size/disposition aliases to Attachment for mails.dev compat.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: guo-yu