feat: optimize async execution

[tyaroshko]

Note

Medium Risk
Updates core flow/node execution to mix native-async and thread-offloaded sync work, which can affect concurrency, timeouts, and context propagation across many node types. Risk is mitigated by added unit/integration coverage but touches critical runtime paths (LLM execution, caching, executor lifecycle).

Overview
Optimizes async runtime execution paths by introducing native async node execution and isolating sync offloading to a per-Flow.run_async ContextAwareThreadPoolExecutor passed down into nodes.

Nodes now choose between running execute_async directly on the event loop (with new execute_async_with_retry using asyncio.wait_for/asyncio.sleep) or falling back to run_sync in an executor with explicit contextvars propagation; tools with their own event loops (e.g. CuaDesktopTool, E2BDesktopTool) are forced onto the thread-executor path.

Adds async-aware caching via cache_wf_entity_async (thread-offloading cache I/O), introduces BaseLLM.execute_async using litellm.acompletion (including async streaming handling), and extends LLM fallback logic to the async run_async path. Tests are updated/added to cover async caching, per-flow executors, node async routing/retry/timeout, and LLM async execution/fallback, with expectations adjusted (e.g., async LLM calls no longer pass a sync client).

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[github-actions]

Coverage Report •

File	Stmts	Miss	Cover	Missing
dynamiq/flows
flow.py	235	57	75%	105, 112, 119, 153–154, 212–214, 236, 239, 245, 247–251, 258, 261, 267, 269, 271–272, 274, 276–278, 428–432, 442–443, 457–458, 460, 479–480, 482, 485, 504–505, 508–509, 512–513, 515–516, 519–521, 523–527, 529
dynamiq/nodes
node.py	776	119	84%	53, 284, 332, 349, 382, 393, 408, 413–414, 418–419, 463–464, 466, 484, 503, 505, 539, 541, 548–549, 621–622, 625–627, 634–636, 644–645, 655–660, 667–668, 743, 756, 758, 760, 764, 775–776, 794–797, 800–803, 805, 810, 812–814, 818, 821–822, 827, 849–851, 857, 1252–1253, 1256–1258, 1261, 1264–1265, 1267, 1355, 1389–1390, 1415–1416, 1438–1439, 1467–1468, 1494–1495, 1520–1521, 1543–1544, 1564–1565, 1603, 1631, 1637, 1640, 1657–1659, 1732–1738, 1740, 1742–1743, 1754, 1774, 1809, 1843, 1849, 1902, 1924–1926
dynamiq/nodes/llms
base.py	355	36	89%	31, 33, 140, 146, 342–345, 352–358, 385, 562–571, 592–593, 626, 628, 658, 860, 937, 940, 971–972
tests
conftest.py	99	1	98%	141
TOTAL	26978	8975	66%

Tests	Skipped	Failures	Errors	Time
1572	1 💤	0 ❌	0 🔥	2m 2s ⏱️

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