DimSim: e2e eval tests not running

[Viswa4599]

Problem

Paul reports tests don't run:

pytest dimos/e2e_tests/test_dimsim_eval.py -v -s -m slow

To Investigate

• Check if DIMSIM_HEADLESS=1 and system Chrome are required
• macOS Gatekeeper quarantine blocking compiled binary (xattr -c)
• Playwright/Chrome setup for headless eval
• @pytest.mark.slow marker applied correctly
• Test on fresh checkout

Context: dimos team feedback on PR #1390.

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Synced from DIM-779 by summer