Fix ToolNode parallel interrupts aggregation

[osasisorae]

I updated ToolNode to collect interrupts from every parallel tool execution (sync + async) before bubbling them up because the previous executor only surfaced whichever call finished first.

I added regression coverage for the sync, async, and resume flows because we needed tests that prove all three tool calls halt, resume in order, and return their tool messages.

I ran make format, make lint, test_tool_node.py -k interrupt, and test_tool_node.py -k interrupt' because those hit the files we touched; full make test still requires Docker (Postgres/Redis) if you want to run it.

[vercel]

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