赵月辉 / fastgpt-migrated

* feat(s3): add short access links

* refactor(s3): extract access link sdk core

* fix(s3): resolve access link sdk alias in pro tests

* fix: persist invoke uploaded files

* feat: support s3 short redirect download mode

* docs: add s3 refactor design docs

* refactor: improve s3 upload policy handling

* fix: support aborting chat file uploads

* feat: support public download shortlink prefix

* fix: resolve public shortlink file metadata

* fix: restore shortlink media in chat context

* fix: persist sandbox files with chat lifecycle

* fix: align dropped files with upload config

* fix: reject mismatched explicit upload types

* fix: await dataset preview access links

* fix: align pro chat file persistence

* fix(chat): secure draft file upload policies

* fix(chat): preserve first-turn media file types

* perf(s3): reduce download alias lease writes

* fix(chat): preserve first-turn media metadata

* perf(s3): batch download access link issuance

* fix(s3): release aborted proxy download streams

* test(s3): align checks with stream lifecycle

* fix: resolve shortlink CI build failures

* docs: consolidate s3 refactor design