fix(dsh): use producer-owned source kind for Session format v4 compatibility

[bobbyreader]

Summary

Fixes SessionFormatError: format v4 message requires a producer-owned source kind in DeepSeek Harness (DSH >= 0.10.0 / Session format v4).

Problem

In DSH 0.10.0 (Session format v4), message sources with kind: 'plugin' have been deprecated and rejected in favor of producer-owned source kinds (plugin:<plugin-name>). When @memtensor/memos-local-plugin injected memory recall context or created auxiliary user messages for host LLM calls with source: { kind: 'plugin', plugin: 'memos-local-memory' }, DSH's session format validator rejected the message and crashed the session turn during projection/persistence.

Fix

• Updated createRecallMessage in adapters/deepseek-harness/index.ts to use source: { kind: \plugin:${DEEPSEEK_HARNESS_PLUGIN}`, form: 'recall' }`.
• Updated toDshMessage in adapters/deepseek-harness/host-llm.ts to use source: { kind: \plugin:${HOST_LLM_MESSAGE_SOURCE}` }`.
• Updated corresponding test assertions and fixtures in deepseek-harness-bridge.test.ts and deepseek-harness-host-llm.test.ts.

Validation

• Tested and verified live in DSH Desktop 0.10.0 with automatic recall and multi-turn turns.
• Aligned with DSH Session format v4 schema requirements.

🤖 Generated with Claude Code