AI Agent → localhost:8473 → Fishnet Proxy → External API
  (untrusted)                (enforces policy)   (internet)

// Agent code uses localhost proxy
fetch('http://localhost:8473/proxy/openai/v1/chat/completions', {
  method: 'POST',
  headers: { 'Content-Type': 'application/json' },
  body: JSON.stringify({ model: 'gpt-4', messages: [...] })
})

let plaintext = Self::decrypt_with_key(
    key.key_array(), 
    &nonce_bytes, 
    &encrypted_key
)?;
let key_str = String::from_utf8(plaintext)
    .map_err(|_| VaultError::InvalidUtf8)?;

let leaf_hash = merkle::hash_audit_leaf(&leaf_payload);
let root = merkle::insert_leaf_and_new_parents(
    &tx, 
    id, 
    id.saturating_sub(1), 
    leaf_hash
)?;

let public_routes = Router::new()
    .route("/api/auth/status", get(auth::status))
    .route("/api/auth/setup", post(auth::setup))
    .route("/api/auth/login", post(auth::login));

let protected_routes = Router::new()
    .route("/api/status", get(system::status))
    .route("/api/policies", get(system::get_policies).put(system::put_policies))
    .route("/api/credentials", get(vault::list_credentials))
    .route("/api/audit", get(audit::list_audit))
    .layer(axum_middleware::from_fn_with_state(
        state.clone(),
        middleware::require_auth,
    ));

let proxy_routes = Router::new()
    .route("/proxy/{provider}/{*rest}", any(proxy::handler))
    .route("/binance/{*rest}", any(proxy::binance_handler))
    .route("/custom/{name}/{*rest}", any(proxy::custom_handler))
    .layer(DefaultBodyLimit::max(constants::MAX_BODY_SIZE));