docs: Add upstream merge log for 2026-03-13 (Round 2, 21 commits)

Cherry-picked 21 upstream commits with zero conflicts.
All 4 local superiority features verified intact.
Test results: 3093 passed, 1 flaky upstream test, 74 skipped.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: Developer

UPSTREAM_MERGE_LOG_2026-03-13.md

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+# Upstream Merge Log — 2026-03-13 (Round 2)
+
+## Summary
+
+Cherry-picked 21 new upstream commits from `langchain-ai/deepagents` (main) into `upstream-sync-2026-03-13` branch.
+
+- **Total commits**: 21 cherry-picked + 1 local (converters integration)
+- **Conflicts**: 0 (1 auto-resolved trivially)
+- **Local superiority**: All 4 features preserved
+
+## Commits Merged (newest first)
+
+| # | Commit | Description |
+|---|--------|-------------|
+| 21 | 6d018bc2 | chore(examples): update nvidia model (#1855) |
+| 20 | 2e820148 | feat(sdk): Add LangSmith integration metadata (#1837) |
+| 19 | 9742a1f9 | fix(sdk): strip leading slash from glob patterns (#1846) |
+| 18 | e2164804 | feat(sdk): add MemoryAgentBench evaluation suite (#1807) |
+| 17 | e7843f28 | chore(deps): bump setup-uv@v6 to v7 (#1848) |
+| 16 | 7b94dc27 | fix(sdk): accept all langsmith tracing env vars in evals (#1847) |
+| 15 | fcab741d | feat(cli): client-server architecture via langgraph dev (#1759) |
+| 14 | a7b61f71 | chore(deps): bump multipart 1.3.0→1.3.1 daytona (#1842) |
+| 13 | e3e9c32b | chore(deps): bump multipart 1.3.0→1.3.1 harbor (#1843) |
+| 12 | 006396e0 | chore(deps): bump multipart 1.3.0→1.3.1 cli (#1841) |
+| 11 | 956eef47 | test(sdk): add 3 more evals for tool usage (#1840) |
+| 10 | dd8857f3 | chore(sdk): add evals README, ensure tracing (#1834) |
+| 9 | 4dd0f0bb | fix(cli): use max-height for tool-info-scroll (#1835) |
+| 8 | 4a58b57c | feat(cli): enable ask_user tool by default (#1830) |
+| 7 | aa4ce4c9 | feat(cli): show model status in /model selector (#1820) |
+| 6 | 2b90ac9c | feat(examples): add nvidia deep agent (#1822) |
+| 5 | 3c656494 | feat(sdk): add subagent_model param (#1369) |
+| 4 | a2829c9a | fix(cli): use UUID7 for thread IDs (#1826) |
+| 3 | 24ee68bb | refactor(sdk): extract model resolution into _models module (#1825) |
+| 2 | cb4da307 | fix(cli): prevent reentrant model switching (#1824) |
+| 1 | 95a7693e | feat(cli): add sessions alias for /threads (#1823) |
+
+## Local Superiority Verification
+
+| Feature | File | Status |
+|---------|------|--------|
+| Memory async/sync (isawaitable) | middleware/memory.py | Preserved |
+| SubAgent logging | middleware/subagents.py | Preserved |
+| SkillsMiddleware V2 (1190 lines) | middleware/skills.py | Preserved |
+| create_summarization_tool_middleware | middleware/summarization.py | Preserved |
+
+## Test Results
+
+| Suite | Passed | Failed | Skipped | Notes |
+|-------|--------|--------|---------|-------|
+| SDK unit tests | 850 | 0 | 73 | All green |
+| CLI unit tests | 2238 | 1 | 1 | 1 flaky upstream test (autocomplete timing) |
+| Daytona tests | 5 | 0 | 0 | All green |
+| **Total** | **3093** | **1** | **74** | |
+
+### CLI Test Failure (non-blocking)
+
+- `test_chat_input.py::TestHistoryRecallSuppressesCompletions::test_history_recall_does_not_trigger_completions`
+- Race condition in Textual UI test — autocomplete suggestions appear despite history recall
+- This is an upstream test issue, not a regression from merge
+
+## Key New Features
+
+1. **_models module** (`_models.py`): Model resolution helpers extracted from graph.py
+2. **subagent_model param**: `create_deep_agent()` now accepts `subagent_model` for per-subagent model configuration
+3. **Glob pattern fix**: CompositeBackend now strips leading slashes from glob patterns
+4. **LangSmith metadata**: `ls_integration: deepagents` added to graph config
+5. **MemoryAgentBench**: Evaluation suite in `tests/evals/`
+6. **Client-server CLI**: `langgraph dev` architecture for CLI
+7. **ask_user by default**: Tool enabled without configuration
+8. **UUID7 thread IDs**: More sortable than 8-char hex
+9. **NVIDIA example**: New deep agent example
+
+## Version
+
+SDK version after merge: 0.4.10