[mfederowicz]

Trakt's contract now documents that sync/collection add clears metadata a request leaves out (trakt/trakt-api ae20b2f). Two problems in sync -a add_to_collection:

Fixed

• hdr from an export made with -ex metadata was never sent: no UpdateCollectedData in str/ copied Metadata.Hdr, so re-adding an export could clear the HDR format. It is now sent with the other metadata.
• add_to_collection -t shows with an export made without -ex metadata crashed with a nil pointer error (season episodes without metadata). Those episodes are now sent without metadata.

Tests

• str/export_list_item_test.go: hdr copied by all five methods; season episode without metadata / collected_at.
• handlers/commons_pure_test.go: both export shapes through ConvertBytesToItemsList for add_to_collection.
• Both fail without the fix (hdr asserts fail, shows case panics).

Live check (2026-11-04)

• Re-adding one collected show as exported without metadata (86 episodes): existing.episodes=86, added/updated 0, not_found empty; before the fix it crashed before the request.
• hdr is mock-tested only: no collected item on the test account has HDR set.

AI (Claude Code) traced the contract change to the bugs, wrote the fix, tests, CHANGELOG entry and the live-check script; I ran the live check.