Add the pinned Eve loopback executor

[ferueda]

Summary

• add the loopback-only HTTP Basic-authenticated Eve executor adapter
• separate health and info preflight from exact-job execution and claim authority
• validate the pinned runtime model, route, options, instructions, and tool surface
• parse only the frozen Eve 0.27.8 stream-format-19 lifecycle
• bound transport data and sanitize every retained failure

Review path

1. Start with internal/adapters/eve/preflight.go for runtime attestation.
2. Read internal/adapters/eve/executor.go for request and session execution.
3. Read internal/adapters/eve/stream.go for the strict streaming state machine.
4. Use executor_test.go for bounds, redirects, malformed streams, and failure cascades.

Boundaries

No CLI wiring or live call. Routine tests use synthetic HTTP fixtures. There are no fallback branches for other Eve or stream versions.

Verification

• make check on the rebuilt combined slice
• focused Eve tests included in the full gate

Stack

Based on #25 so the review stack is linear.

[ferueda]

Superseded by #20. Noema will not call or attest Eve directly, so this Go executor adapter is no longer part of the architecture. The branch remains available for reference if an independent consumer later needs a small transport adapter.