feat(m7.3): cross-tenant admin HTTP endpoints

Adds two cross-tenant operator endpoints on top of the M7.2-D
DatabasePool primitives:
- GET    /api/v1/admin/tenants              → list tenant DBs
- DELETE /api/v1/admin/tenants/{tenant_id}  → drop (GDPR delete)

Auth is a static bearer (ADMIN_API_TOKEN env), explicitly NOT a
Keycloak JWT — the whole point is to operate across tenants and a
customer JWT always carries a single tenant_id, which would be a
semantic conflict. Comparison is constant-time to avoid byte-level
timing probes.

Design
- ADMIN_API_TOKEN env on the agent. When unset, the admin routes
  aren't mounted at all (404 rather than 401). An operator who
  hasn't opted in can't fingerprint the surface.
- Admin sub-router is built in start_api_server when the token is
  configured, then merged into the main router with its own
  require_admin_token middleware.
- compliance-core::auth gains a PUBLIC_PREFIXES list. Paths under
  /api/v1/admin/ bypass require_jwt_auth so the customer JWT path
  and the admin token path never collide.
- require_tenant_status passes through naturally — admin requests
  carry no TenantContext.

Files
- compliance-core/src/auth.rs — PUBLIC_PREFIXES + prefix-aware skip.
- compliance-core/src/config.rs — admin_api_token + tenant_registry_url
  fields on AgentConfig. tenant_registry_url is added now so the
  scheduler→registry PR doesn't have to bump the config shape again.
- compliance-agent/src/config.rs — env wiring for both.
- compliance-agent/src/api/handlers/admin.rs (new) — list_tenant_dbs,
  drop_tenant_db, require_admin_token middleware, tokens_eq helper
  with a small test.
- compliance-agent/src/api/server.rs — conditional admin sub-router
  + merge.
- Test harness fixtures updated for the two new config fields.

Test plan
- cargo fmt --all clean
- cargo clippy --workspace --exclude compliance-dashboard
  -- -D warnings clean
- cargo test -p compliance-core --lib — 7 pass
- cargo test -p compliance-agent --lib — 229 pass (+1 new for
  tokens_eq)

Production
- Set ADMIN_API_TOKEN in orca-infra (per-secret, NOT committed) when
  ready to expose these endpoints. Without the env, the routes
  literally don't exist on the binary.
- Long-term: replace the static bearer with a dedicated admin realm
  in Keycloak. Token rotation is just an env change + restart for
  now; revocation responsiveness is zero.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

compliance-agent/src/api/handlers/admin.rs

@@ -0,0 +1,115 @@
+//! Cross-tenant admin endpoints (`/api/v1/admin/*`).
+//!
+//! Operator-only. Auth is a **static bearer token** (`ADMIN_API_TOKEN`
+//! env on the agent) — explicitly NOT a Keycloak JWT, because the
+//! whole point of these endpoints is to operate ACROSS tenants. A
+//! customer JWT (which always carries a single tenant_id) has no
+//! business mounting them.
+//!
+//! Routes are only registered when `ADMIN_API_TOKEN` is set. With no
+//! token, the endpoints don't exist at all (404), which is a stronger
+//! guarantee than "401 if you guess the path".
+//!
+//! Operations:
+//! - `GET    /api/v1/admin/tenants`              — list tenant DBs
+//! - `DELETE /api/v1/admin/tenants/{tenant_id}`  — GDPR delete
+//!
+//! Tenant ids in URLs are passed as-is to `DatabasePool::drop_tenant`,
+//! which sanitises them the same way it does for creation. Listing
+//! returns the raw DB names from `list_tenant_db_names` — operators
+//! can reverse-derive the tenant_id from the prefix.
+
+use axum::extract::{Extension, Path, Request};
+use axum::http::{header, StatusCode};
+use axum::middleware::Next;
+use axum::response::{IntoResponse, Response};
+use axum::Json;
+use secrecy::ExposeSecret;
+use serde::Serialize;
+
+use super::dto::AgentExt;
+
+#[derive(Serialize)]
+pub struct ListTenantDbsResponse {
+    pub tenant_db_names: Vec<String>,
+}
+
+#[tracing::instrument(skip_all)]
+pub async fn list_tenant_dbs(
+    Extension(agent): AgentExt,
+) -> Result<Json<ListTenantDbsResponse>, StatusCode> {
+    let names = agent.db_pool.list_tenant_db_names().await.map_err(|e| {
+        tracing::error!("admin: list_tenant_db_names failed: {e}");
+        StatusCode::INTERNAL_SERVER_ERROR
+    })?;
+    Ok(Json(ListTenantDbsResponse {
+        tenant_db_names: names,
+    }))
+}
+
+#[tracing::instrument(skip_all, fields(tenant_id = %tenant_id))]
+pub async fn drop_tenant_db(
+    Extension(agent): AgentExt,
+    Path(tenant_id): Path<String>,
+) -> Result<Json<serde_json::Value>, StatusCode> {
+    agent.db_pool.drop_tenant(&tenant_id).await.map_err(|e| {
+        tracing::error!("admin: drop_tenant failed: {e}");
+        StatusCode::INTERNAL_SERVER_ERROR
+    })?;
+    Ok(Json(serde_json::json!({ "status": "dropped" })))
+}
+
+/// Constant-time-ish comparison of the configured admin token against
+/// the incoming bearer. Uses `subtle`-style byte equality so timing
+/// attacks can't probe the token character by character.
+fn tokens_eq(a: &str, b: &str) -> bool {
+    if a.len() != b.len() {
+        return false;
+    }
+    let mut diff = 0u8;
+    for (x, y) in a.bytes().zip(b.bytes()) {
+        diff |= x ^ y;
+    }
+    diff == 0
+}
+
+/// Middleware enforcing the static `ADMIN_API_TOKEN`. Mounted only on
+/// the admin sub-router, so this never runs on customer routes.
+pub async fn require_admin_token(
+    Extension(agent): AgentExt,
+    request: Request,
+    next: Next,
+) -> Response {
+    let Some(expected) = agent.config.admin_api_token.as_ref() else {
+        // Belt-and-braces — if the routes were somehow mounted without
+        // a token configured, refuse rather than no-op-pass.
+        return (StatusCode::NOT_FOUND, "admin disabled").into_response();
+    };
+    let presented = request
+        .headers()
+        .get(header::AUTHORIZATION)
+        .and_then(|v| v.to_str().ok())
+        .and_then(|s| s.strip_prefix("Bearer "))
+        .map(|s| s.trim());
+    let Some(presented) = presented.filter(|s| !s.is_empty()) else {
+        return (StatusCode::UNAUTHORIZED, "Missing bearer token").into_response();
+    };
+    if !tokens_eq(presented, expected.expose_secret()) {
+        return (StatusCode::UNAUTHORIZED, "Invalid admin token").into_response();
+    }
+    next.run(request).await
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn tokens_eq_basic() {
+        assert!(tokens_eq("abc", "abc"));
+        assert!(!tokens_eq("abc", "abd"));
+        assert!(!tokens_eq("abc", "abcd"));
+        assert!(!tokens_eq("", "x"));
+        assert!(tokens_eq("", ""));
+    }
+}

compliance-agent/src/api/handlers/mod.rs

@@ -1,3 +1,4 @@
+pub mod admin;
 pub mod chat;
 pub mod dast;
 pub mod dto;

compliance-agent/src/api/server.rs

@@ -4,7 +4,8 @@ use axum::extract::Request;
 use axum::http::HeaderValue;
 use axum::middleware::Next;
 use axum::response::Response;
-use axum::{middleware, Extension};
+use axum::routing::{delete, get};
+use axum::{middleware, Extension, Router};
 use tokio::sync::RwLock;
 use tower_http::cors::CorsLayer;
 use tower_http::set_header::SetResponseHeaderLayer;
@@ -14,6 +15,7 @@ use compliance_core::auth::{require_jwt_auth, require_tenant_status, JwksState};
 use compliance_core::{TenantContext, TenantStatus};
 
 use crate::agent::ComplianceAgent;
+use crate::api::handlers;
 use crate::api::routes;
 use crate::error::AgentError;
 
@@ -50,7 +52,28 @@ pub async fn inject_dev_tenant(mut request: Request, next: Next) -> Response {
 }
 
 pub async fn start_api_server(agent: ComplianceAgent, port: u16) -> Result<(), AgentError> {
+    // Admin sub-router. Routes are only mounted when ADMIN_API_TOKEN is
+    // configured — without it, the paths don't exist at all (404 rather
+    // than 401), so an operator who hasn't opted in can't fingerprint
+    // the surface area.
+    let admin_router: Router = if agent.config.admin_api_token.is_some() {
+        tracing::info!("Admin API enabled — /api/v1/admin/* mounted behind ADMIN_API_TOKEN bearer");
+        Router::new()
+            .route(
+                "/api/v1/admin/tenants",
+                get(handlers::admin::list_tenant_dbs),
+            )
+            .route(
+                "/api/v1/admin/tenants/{tenant_id}",
+                delete(handlers::admin::drop_tenant_db),
+            )
+            .layer(middleware::from_fn(handlers::admin::require_admin_token))
+    } else {
+        Router::new()
+    };
+
     let mut app = routes::build_router()
+        .merge(admin_router)
         .layer(Extension(Arc::new(agent.clone())))
         .layer(CorsLayer::permissive())
         .layer(TraceLayer::new_for_http())

compliance-agent/src/config.rs

@@ -59,5 +59,7 @@ pub fn load_config() -> Result<AgentConfig, AgentError> {
             .unwrap_or(true),
         pentest_imap_username: env_var_opt("PENTEST_IMAP_USERNAME"),
         pentest_imap_password: env_secret_opt("PENTEST_IMAP_PASSWORD"),
+        admin_api_token: env_secret_opt("ADMIN_API_TOKEN"),
+        tenant_registry_url: env_var_opt("TENANT_REGISTRY_URL"),
     })
 }

compliance-agent/src/pentest/cleanup.rs

@@ -339,6 +339,8 @@ mod tests {
             pentest_imap_tls: true,
             pentest_imap_username: None,
             pentest_imap_password: None,
+            admin_api_token: None,
+            tenant_registry_url: None,
         }
     }
 

compliance-agent/tests/common/mod.rs

@@ -66,6 +66,8 @@ impl TestServer {
             pentest_imap_tls: false,
             pentest_imap_username: None,
             pentest_imap_password: None,
+            admin_api_token: None,
+            tenant_registry_url: None,
         };
 
         let agent = ComplianceAgent::new(config, db_pool);

compliance-core/src/auth.rs

@@ -63,16 +63,24 @@ struct Claims {
 
 const PUBLIC_ENDPOINTS: &[&str] = &["/api/v1/health"];
 
+/// Path prefixes that bypass JWT validation. The admin sub-router
+/// (`/api/v1/admin/*`) has its own static-bearer middleware and must
+/// not be routed through the customer-JWT path — a Keycloak token
+/// always carries a single tenant_id and would semantically conflict
+/// with cross-tenant admin operations.
+const PUBLIC_PREFIXES: &[&str] = &["/api/v1/admin/"];
+
 /// Middleware that validates Bearer JWT tokens against Keycloak's JWKS
 /// and attaches a `TenantContext` extension on success.
 ///
-/// Skips validation for the health endpoint.
-/// If `JwksState` is not present (Keycloak not configured), requests
-/// pass through and downstream code must handle the missing context.
+/// Skips validation for the health endpoint and any path under one of
+/// the [`PUBLIC_PREFIXES`]. If `JwksState` is not present (Keycloak
+/// not configured), requests pass through and downstream code must
+/// handle the missing context.
 pub async fn require_jwt_auth(mut request: Request, next: Next) -> Response {
     let path = request.uri().path();
 
-    if PUBLIC_ENDPOINTS.contains(&path) {
+    if PUBLIC_ENDPOINTS.contains(&path) || PUBLIC_PREFIXES.iter().any(|p| path.starts_with(p)) {
         return next.run(request).await;
     }
 

compliance-core/src/config.rs

@@ -37,6 +37,15 @@ pub struct AgentConfig {
     pub pentest_imap_tls: bool,
     pub pentest_imap_username: Option<String>,
     pub pentest_imap_password: Option<SecretString>,
+    /// Static bearer for the cross-tenant admin endpoints under
+    /// `/api/v1/admin/*`. When `None`, those endpoints are not
+    /// mounted at all (defense-in-depth: ops endpoints never reach
+    /// any auth path if no operator has explicitly opted in).
+    pub admin_api_token: Option<SecretString>,
+    /// Live tenant-registry URL the scheduler consults for the list
+    /// of tenants to iterate. When `None` or unreachable, scheduler
+    /// falls back to `SCHEDULER_TENANT_IDS` env (M7.2-C).
+    pub tenant_registry_url: Option<String>,
 }
 
 #[derive(Clone, Debug, Serialize, Deserialize)]