Confirmed against the real B2 account: the web-console "Share everything..." presets
write DOWNLOAD-only CORS (s3_get/s3_head, b2_download_*) with NO s3_put/s3_post, so
bitvid's browser uploads CORS-fail. The web UI can't set custom rules — it points
users at the B2 CLI.
Adds a "CORS setup help" button (shown for B2 / Custom S3, hidden for R2) that opens a
modal with:
- the exact CORS rules JSON in B2-native shape (upload + ranged-playback ops; origins
pre-filled from getCorsOrigins()), with a Copy button,
- the `b2 update-bucket --corsRules '<json>' <bucket> allPublic` command to apply it,
- step-by-step + the "use a key with writeBucketCors and bitvid sets it for you" tip.
CORS logic extracted to js/ui/profileModal/storageCorsHelp.js (pure builders +
StorageCorsHelp modal controller) so ProfileStorageController stays under the 1000-line
cap. Tests: tests/storage-cors-help.test.mjs (8 — asserts the rules include the upload
ops the presets omit, origin pre-fill, command shape, modal open/close/visibility).
Build + lint clean; profile-modal + storage suites 32/32.
Co-Authored-By: Claude Opus 4.8 <[email protected]>
