v0.4.0 - Omnigent Backend for MetaHarness

Highlights

This release adds experimental Omnigent support to MetaHarness.

MetaHarness can now use omni run as a proposer backend, letting Omnigent generate candidate harness improvements
while MetaHarness keeps its existing optimization loop: candidate workspaces, validation, scoring, diffs, ledgers,
frontier selection, and experiment artifacts.

Added

• Experimental OmnigentCliBackend
• backend: "omnigent" support in coding-tool project configs
• Generated per-candidate Omnigent agent bundle at .metaharness/omnigent_agent/config.yaml
• Artifact copy of generated agent config at proposal/omnigent_agent.yaml
• Mapping from allowed_write_paths to Omnigent sandbox write paths
• Generated metaharness_enforce_sandbox policy
• Omnigent event parser for JSON, JSONL, and SSE-style streams
• Telemetry import into proposal artifacts
• New examples/omnigent_agent_benchmark

Verified

Real Omnigent smoke test:

• benchmark: examples/omnigent_agent_benchmark
• backend: omnigent
• result: best_candidate_id=c0001
• objective: 0.875
• scope violations: none