v6.8.0

• fix: satisfy BM25 source anchor lint
• feat: unify agent tools and exact SDK runs
• fix(protocol): type event page ordering state
• chore: align 6.8.0 release versions
• fix(protocol): bind runs to artifact identity
• feat(protocol): multiplex native harness sessions
• feat(protocol): bound durable event records
• feat(protocol): expose run state wire names
• feat(protocol): expose event record validation
• feat(protocol): validate command receipts independently
• feat(protocol): own harness transport surface
• feat(protocol): bind commands to code runs
• feat(protocol): define headless agent runtime contract
• feat(serve): expose observable daemon lifecycle
• fix(hooks): expose denial context and retryability
• test(core): lock agent-dir nested governance
• fix(sdk): expose governed host tool calls
• fix(core): make git dependency self-contained
• feat(core): add governed host tool calls
• fix(core): restore Windows HTTP body compatibility