Add Benaiah ACP agent

[benaiah3]

What changed

• Adds Benaiah 1.0.0 to the ACP Registry.
• Uses the published benaiah-acp@1.0.0 npm distribution.
• Adds the required monochrome 16x16 registry icon.

Why

Benaiah implements ACP for use inside compatible editors and clients, with local tools, persistent sessions, MCP passthrough, and five native effort levels.

User impact

Once merged, ACP clients can discover and install Benaiah from the official Registry. New users are offered the benaiah-setup Terminal Auth method before starting a session.

Validation

• npm view benaiah-acp@1.0.0 confirms the pinned public package.
• uv run --with jsonschema .github/workflows/build_registry.py --dry-run validates 40 agents successfully.
• uv run --with agent-client-protocol .github/workflows/verify_agents.py --auth-check --agent benaiah --clean --auth-timeout 120 passes with Auth OK: benaiah-setup(terminal).
• Workflow test suite: 121 passed.
• Ruff lint and format checks pass.

[benaiah3]

Hi maintainers — this first-time contributor PR is ready for review, but the Build Registry workflow is currently action_required and needs maintainer approval before it can run. The candidate passes the registry build, auth validation, full test suite, and Ruff checks locally. Would you please approve the workflow when convenient? Thank you.