Restore all 147 historical canonical fixtures changed by the lower branch to exact shared base 220ff708e3628a9be46d9747d09af6d8cd742f0d bytes (145 V2 and two V0). All 180 committed V0/V1/V2 canonical files now have zero diff against that base, including unchanged Python, test-support and preview sources.
Preserve corrected lower writer bodies in 146 V3 successors across 119 owner directories: replace 135 unreleased V3 counterparts and add 11 siblings. Change only each copied Session header version; preserve all body bytes, raw model streams, inline images, IDs, references and historical delivery generation markers. Remove two unshipped V2 additions after creating their V3 sibling: record-suite/rec-pin and empty-response-retry-current.
Keep six explicitly historical snapshot owners pinned with no V3 sibling. Restore the two pre-step V0 record child sources without synthesizing current output. Fix seven embedded Session header versions in exactly five test-support behavior owners whose output filenames already select V3. Leave protocol expectations, shared references, sidecars, consumer scripts and production migration/normalization code untouched.
Validation: purpose-built temporary Python inventory and verifier checked 337 canonical headers, 3714 successor JSON rows, message roles, contiguous child roles, exact successor bodies, all 180 historical base bytes and zero git diff, noncanonical JSONL immutability, six retained owners and six unchanged preview fixtures. git diff --cached --check passed. Temporary generators removed. Strict migration, native refresh and replay remain pending parent integration; unsupported pre-step sources are reported separately.
The representation PR left child and restart recordings in the old header-system representation while the packaged writer emits system/message before entered user messages. Restart result expectations also retained standalone assistant/chunk notifications after the writer moved stream records into assistant/message. These are stale expected artifacts, not fields to erase in normalization.
Regenerate the owning advanced and restart scenarios through the native macOS ARM64 packaged dsh runtime. Retain messages, tool effects, typed feedback and packed streams; update only the missing system nodes and their sequence references, and remove obsolete standalone chunk notifications. The advanced parent result and parent session already match the writer after the rebase, so this commit changes only two child logs and the restart result/logs.
Validation: pnpm run build; pnpm exec tsx scripts/build-exe-for-python-sdk.ts --skip-build --targets=node24-macos-arm64; uv run --project python/sdk python scripts/smoke-python-runtime.py --scenario sdk-snapshot --exe dist-exe/deepseek-harness-sdk-runtime-macos-arm64 and the equivalent sdk-restart command each reproduced the mismatch, then passed with --update-snapshots and again without it. Both read-only reruns pass. Other native targets remain covered by exact-head CI.
Consolidate the representation-change PR and its rebase reconciliations into one baseline. Preserve the exact tree and keep the in-history feature in the dependent PR. Follow-up fixes remain separate.
Tianyi Cui