feat(dockerhub): add POST /dockerhub/events analytics endpoint

The stack builder UI (ServiceDockerhub.jsx) fires POST requests to
/api/builder/dockerhub/events to log autocomplete interactions. The
Next.js proxy forwards them to stacker at POST /dockerhub/events, but
no such route existed — Casbin denied it with 403.

- Add log_event handler: accepts {event, payload} JSON body, logs via
  tracing at DEBUG level, returns 204 No Content (fire-and-forget)
- Register in startup.rs under /dockerhub scope
- Add Casbin migration granting group_user and group_admin POST access

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: vsilent

migrations/20260331132000_casbin_dockerhub_events_rule.down.sql

@@ -0,0 +1,2 @@
+DELETE FROM public.casbin_rule
+WHERE ptype = 'p' AND v1 = '/dockerhub/events' AND v2 = 'POST';

migrations/20260331132000_casbin_dockerhub_events_rule.up.sql

@@ -0,0 +1,8 @@
+-- Allow authenticated users to post DockerHub autocomplete analytics events
+INSERT INTO public.casbin_rule (ptype, v0, v1, v2, v3, v4, v5)
+VALUES ('p', 'group_user', '/dockerhub/events', 'POST', '', '', '')
+ON CONFLICT DO NOTHING;
+
+INSERT INTO public.casbin_rule (ptype, v0, v1, v2, v3, v4, v5)
+VALUES ('p', 'group_admin', '/dockerhub/events', 'POST', '', '', '')
+ON CONFLICT DO NOTHING;

src/routes/dockerhub/mod.rs

@@ -2,8 +2,9 @@ use std::sync::Arc;
 
 use crate::connectors::{DockerHubConnector, NamespaceSummary, RepositorySummary, TagSummary};
 use crate::helpers::JsonResponse;
-use actix_web::{get, web, Error, Responder};
+use actix_web::{get, post, web, Error, HttpResponse, Responder};
 use serde::Deserialize;
+use serde_json::Value;
 
 #[derive(Deserialize, Debug)]
 pub struct AutocompleteQuery {
@@ -86,6 +87,16 @@ pub async fn list_tags(
         .map_err(Error::from)
 }
 
+/// Receive a DockerHub autocomplete analytics event from the stack builder UI.
+/// The payload is `{event: string, payload: any}` — logged and discarded.
+/// Returns 204 No Content so the browser's fire-and-forget fetch succeeds.
+#[tracing::instrument(name = "dockerhub_log_event", skip(body))]
+#[post("/events")]
+pub async fn log_event(body: web::Json<Value>) -> HttpResponse {
+    tracing::debug!(event = ?body, "dockerhub autocomplete event received");
+    HttpResponse::NoContent().finish()
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;

src/startup.rs

@@ -158,7 +158,8 @@ pub async fn run(
                 web::scope("/dockerhub")
                     .service(crate::routes::dockerhub::search_namespaces)
                     .service(crate::routes::dockerhub::list_repositories)
-                    .service(crate::routes::dockerhub::list_tags),
+                    .service(crate::routes::dockerhub::list_tags)
+                    .service(crate::routes::dockerhub::log_event),
             )
             .service(
                 web::scope("/admin")