* feat(channels): Channel.Send and MediaSender.SendMedia return delivered message IDs
Change Channel.Send signature from (ctx, msg) error to (ctx, msg) ([]string, error)
and MediaSender.SendMedia similarly, so callers can capture platform message IDs
for threading, reactions, and history annotation.
Adapters that return real IDs: Telegram (per-chunk MessageID), Discord (Message.ID),
Slack Send (ts), QQ (sentMsg.ID), Matrix (EventID). Slack SendMedia returns nil
because UploadFileV2 does not expose the posted message timestamp in its response.
All other adapters return nil IDs.
preSend and sendWithRetry in manager.go updated to propagate ([]string, bool).
README examples updated for both English and Chinese docs.
* style: apply golangci-lint fixes (golines)
* docs: fix Send migration guide — restore old error-only signature in before/after example
* fix(media): track cleanup ownership per path
Add explicit cleanup policy handling to MediaStore and count refs by path before deleting the underlying file. This prevents cleanup from removing shared files until the final ref is gone.
Refs #1886
* fix(tools): keep send_file refs forget-only
Mark send_file media registrations as forget-only so cleanup drops the ref without deleting the original workspace file.
Refs #1886
* fix(channels): declare managed media cleanup policy
Explicitly mark downloaded and managed channel media as delete-on-cleanup so media ownership is visible at each registration site.
Refs #1886
Hoshina