Product runtime: private, self-hostable maintainer-assist service

[matedev01]

Turn vanguarstew from an operator-run dev tool into a self-hostable maintainer-assist service that survives restarts and preserves the strict private-review boundary, keeping the existing solve()/benchmark/TEE systems separate from live operations.

Security & publication contract

• Secrets (GitHub token, webhook secret, model key): environment only — never JSON config, logs, or status.
• PR diffs, prompts, review results, private evidence: owner-only local result directory.
• Health endpoints (/healthz,/readyz): loopback-only.
• Live review data never enters benchmark artifacts, Polaris receipts, leaderboards, or GitHub.

Phases

1. Private local foundation — control plane, env-only secrets, durable SQLite queue, read-only GitHub client, signed webhook intake, loopback health, Compose/systemd templates. (first PR)
2. Controlled live pilot (one repo, least-privilege token, outputs stay local, no auto GitHub writes).
3. Operator workflow — authenticated console to inspect and selectively publish a bounded, policy-approved summary.
4. Scale & recovery.

Tracks the openvang/ agent-factory + vanguarstew_runtime/ service split out of a large local branch.