docs(cli): sync SRT upload docs from EF

[miguel-heygen]

What changed

• Sync the generated HyperFrames cloud client documentation with Experiment Framework commit a71c71b8 so /v3/assets advertises SRT subtitle uploads and the .srt type.
• Add a focused source-contract regression test that pins the SRT documentation to the uploadAsset endpoint.

This documents existing upload support; it does not change upload runtime behavior.

Root cause

The Experiment Framework codegen job generated this update successfully, but its GIT_PAT could check out HyperFrames without creating a branch: GitHub returned 404 from the first POST /repos/heygen-com/hyperframes/git/refs write. This PR clears the pending generated-client drift from #2355. The workflow secret still needs repository contents-write and pull-request permissions before automatic syncs can resume.

Verification

• Regenerated from Experiment Framework a71c71b8; client.ts and types.ts match the generator output.
• Captured the regression test failing before the generated documentation update and passing afterward.
• bun run --cwd packages/cli test — 130 files, 1660 tests passed.
• CLI typecheck, focused format/lint, tracked-artifact check, workspace-contract check, and git diff --check pass.

Refs #2355