Gate unauthenticated introspection routes before sensitive config lands in the manifest

[aram356]

Summary

/_mocktioneer/{manifest,config,routes} (framework-supplied by edgezero_core::introspection, added in PR #110) are mounted on all four adapters, including fastly and cloudflare. They are unauthenticated, so on edge deployments the full route table and manifest are publicly enumerable.

This is intentional and safe today — it is a deliberate deploy-time footgun to track, not a live vulnerability.

Why it's safe right now

• The effective app config is only bid_cpm — nothing sensitive.
• Mocktioneer declares no [environment] section, so there is nothing for manifest to leak.
• manifest redacts [environment.secrets]; config leaves #[secret] fields as unresolved key-name references.
• Mocktioneer is a mock bidder — the route table is not sensitive information.
• Documented with a warning in docs/guide/configuration.md (Introspection Routes → "Unauthenticated").

The trigger — when this must be fixed

Harden before any of these land:

• An [environment.variables] section is added to edgezero.toml — manifest emits those verbatim (only [environment.secrets] is redacted).
• Any non-trivial or tenant-specific field is added to MocktioneerConfig.
• Mocktioneer is used for anything beyond public mock traffic.

Options when we do

• Put auth/allowlist middleware in front of the /_mocktioneer/* triggers (shared-token header or IP allowlist).
• Scope the three introspection triggers to adapters = ["axum"] so they exist only on the local/dev adapter.
• Keep them public but assert in a test that [environment.variables] stays empty, so adding one fails loudly.

Notes

• Raised by @prk-Jr in review of Adapt Mocktioneer to edgezero v0.0.4 (extensible CLI, typed config, introspection routes) #110 (flagged non-blocking, by design).
• Decision at the time: keep all four adapters mounted and track the hardening here.