- EmailRepository: add searchEmails(accountId, mailboxPath, query) - EmailRepositoryImpl: UID SEARCH with OR SUBJECT/TEXT criteria, fetch ENVELOPE+FLAGS for matching UIDs - EmailListScreen: toggle search bar in AppBar; submit triggers server search; results replace the stream list; ESC/back closes search - Refactored list into _buildList() shared by stream and search views - README/PLAN.md updated Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>