Phase 1: reframe repo around Agent Contract Protocol

[shreyanshjain7174]

Summary

Move the public repo identity from context/token optimization to governed execution contracts.

Scope

• README leads with execution governance and contract semantics.
• SPEC uses Agent Contract Protocol and Execution Contract terminology.
• Positioning doc includes the 9-layer model and Databricks analogy.
• Launch copy becomes question-led validation copy.

Acceptance Criteria

• A new reader understands ACP as a governance/execution primitive within 30 seconds.
• scripts/check_docs.py passes.
• No stale ninevigil-acp repository references remain.

[shreyanshjain7174]

Closing. The repo was repositioned to Agent Native Format in #22 (merged). The headline is now the token-minimal view format; the execution-contract runtime stays as a secondary component. This phase issue was framed around the old Agent Contract Protocol positioning. If the execution-runtime work is still wanted, reopen and re-scope it under the ANF framing. See naming-decision.md.