DeepSeek Harness incremental imports must keep a session-scoped title

[hawkingrei]

Summary

DeepSeek Harness incremental thread imports derive the thread title from each delta batch. The same stable thread can therefore receive a different --title on every import, and the reconciliation retry can submit a payload whose title does not match the already-built CLI arguments.

Current behavior

buildThreadImportDelta derives payload.title from the delta message list. importSession then captures that title once in baseImportArgs.

Consequences:

• A later delta whose first user message differs can rename the same stable thread.
• After an optimistic append conflict, the full reconciliation payload replaces payload, but baseImportArgs retains the earlier delta title.

Expected behavior

• Thread identity and title remain session-scoped across incremental batches.
• A reconciliation import builds arguments from the reconciliation payload rather than stale delta metadata.
• Exact replay and optimistic append behavior remain unchanged.

Reproduction

1. Build a DSH session with at least two user turns that have different text.
2. Import the first batch and retain its acknowledged cursor.
3. Import the second batch using that cursor.
4. Observe that the second delta derives its title from the later batch rather than the session's first user message.
5. Force an expected-message-count conflict and observe that the reconciliation payload is rewritten while the original baseImportArgs title is reused.

Environment

• Repository: nowledge-co/community
• Integration: nowledge-mem-deepseek-harness-plugin
• Incremental import implementation: commit 3a9b3637c / PR fix(plugins): make automatic session capture incremental #514

Acceptance criteria

• Incremental batches use one stable session-scoped title.
• Reconciliation rebuilds CLI arguments from the reconciliation payload.
• Regression tests cover two deltas with different first messages.
• Regression tests cover conflict-to-full-reconciliation argument rebuilding.

Discovery

Found while reviewing PR #513. Kept separate because the affected code is already on main and is not part of that PR's final diff.

[hawkingrei]

Code-ready in PR #526 at 388c2fc7.

Technical clarification from current Mem server inspection: appending to an existing imported thread does not overwrite its persisted title today. The confirmed defect is still real but narrower than the original consequence statement: delta-scoped titles make submitted CLI arguments and response metadata drift from the payload/session contract, and the conflict retry reused stale arguments after replacing its payload.

The fix now:

• derives the title from the first real user message in the session, not the delta slice;
• stores that title in the live acknowledged cursor so later and compacted event windows retain it;
• rebuilds import arguments from the reconciliation payload;
• keeps checkpoint/idempotency fields only on optimistic append attempts.

Regression evidence:

• JavaScript syntax checks plus plugin Node suite: 7 passed, 0 failed.
• Focused DeepSeek Harness registry/static contract: 1 passed, 32 deselected.
• Full key-plugin suite: the branch and clean origin/main@073e363f have the same 3 unrelated Copilot/WorkBuddy/Kimi failures (3 failed, 23 passed, 7 skipped).
• Ubuntu and Windows GitHub checks pass.
• PR readback: ready/non-draft, MERGEABLE, CLEAN; no review threads.

Known boundary: the title survives compaction while the plugin's live cursor exists. After a process restart with the original user event already compacted away, DSH no longer exposes enough source data to reconstruct that original title; Mem's existing append path still preserves the persisted title.