fix: repair quality gates and land OpenWiki artifacts

[svngoku]

Summary

Master's CI is red: the PR #3 merge emptied docs/exec-plans/active/, which fails the golden-principles gate, and test_numpy_available has been failing because the sandboxed executor crashes on numpy's runtime imports with KeyError: '__import__'. This branch repairs both gates and commits the OpenWiki documentation set that AGENTS.md already advertises.

What changed

• Sandboxed executor (agentic_internet/tools/code_execution.py): the exec namespace now exposes a guarded __import__. C extensions such as numpy resolve imports through the frame's __builtins__ at runtime, so reductions like np.array([1,2,3]).sum() work again. The guard enforces the AST validator's module blocklist, so aliasing __import__ to dodge the AST call check stays blocked.
• Golden gate: docs/exec-plans/active/.gitkeep restores the directory the harness structure check requires, so python3 .opencode/tools/golden_principles.py and CI pass again.
• OpenWiki artifacts: the generated openwiki/ wiki (26 files), the scheduled .github/workflows/openwiki-update.yml workflow, and CLAUDE.md land in the repo. The workflow needs BASETEN_API_KEY (plus optional LangSmith keys) as repository secrets.

Test plan

All five repo gates pass locally: ruff check, ruff format --check, mypy, golden_principles, and pytest (198 passed, up from 195 with 1 failing). New regression tests in tests/test_code_execution.py cover the aliased-import block and allowed runtime imports.