feat: replace instance actor decorator with real DB row

Migration inserts a service actor with a well-known UUID. Removes the
InstanceActorUserRepo wrapper — the real ApUserRepository finds it.

crates/adapters/activitypub/src/instance_actor.rs

@@ -1,57 +0,0 @@
-use std::sync::Arc;
-
-use async_trait::async_trait;
-use k_ap::{ApActorType, ApUser, ApUserRepository};
-
-pub const INSTANCE_ACTOR_ID: uuid::Uuid =
-    uuid::Uuid::from_bytes([0, 0, 0, 0, 0, 0, 0x40, 0, 0x80, 0, 0, 0, 0, 0, 0, 0]);
-
-pub struct InstanceActorUserRepo {
-    inner: Arc<dyn ApUserRepository>,
-    base_url: String,
-}
-
-impl InstanceActorUserRepo {
-    pub fn new(inner: Arc<dyn ApUserRepository>, base_url: String) -> Self {
-        Self { inner, base_url }
-    }
-}
-
-fn instance_ap_user(base_url: &str) -> ApUser {
-    ApUser {
-        id: INSTANCE_ACTOR_ID,
-        username: "instance".to_string(),
-        display_name: None,
-        bio: None,
-        avatar_url: None,
-        banner_url: None,
-        also_known_as: vec![],
-        profile_url: url::Url::parse(base_url).ok(),
-        attachment: vec![],
-        manually_approves_followers: false,
-        discoverable: false,
-        actor_type: ApActorType::Service,
-        featured_url: None,
-    }
-}
-
-#[async_trait]
-impl ApUserRepository for InstanceActorUserRepo {
-    async fn find_by_id(&self, id: uuid::Uuid) -> anyhow::Result<Option<ApUser>> {
-        if id == INSTANCE_ACTOR_ID {
-            return Ok(Some(instance_ap_user(&self.base_url)));
-        }
-        self.inner.find_by_id(id).await
-    }
-
-    async fn find_by_username(&self, username: &str) -> anyhow::Result<Option<ApUser>> {
-        if username == "instance" {
-            return Ok(Some(instance_ap_user(&self.base_url)));
-        }
-        self.inner.find_by_username(username).await
-    }
-
-    async fn count_users(&self) -> anyhow::Result<usize> {
-        self.inner.count_users().await
-    }
-}

crates/adapters/activitypub/src/lib.rs

@@ -1,10 +1,12 @@
 pub mod handler;
-pub mod instance_actor;
 pub mod note;
 pub mod port;
 pub mod service;
 pub mod urls;
 
+pub const INSTANCE_ACTOR_ID: uuid::Uuid =
+    uuid::Uuid::from_bytes([0, 0, 0, 0, 0, 0, 0x40, 0, 0x80, 0, 0, 0, 0, 0, 0, 0]);
+
 pub use handler::ThoughtsObjectHandler;
 pub use note::ThoughtNote;
 pub use port::{
@@ -34,22 +36,18 @@ pub struct ApServiceConfig {
 pub async fn build_ap_service(
     cfg: ApServiceConfig,
 ) -> (Arc<ActivityPubService>, Arc<ApFederationAdapter>) {
-    let user_repo = Arc::new(instance_actor::InstanceActorUserRepo::new(
-        cfg.user_repo,
-        cfg.base_url.clone(),
-    ));
     let mut builder = ActivityPubService::builder(cfg.base_url)
         .activity_repo(cfg.activity_repo)
         .follow_repo(cfg.follow_repo)
         .actor_repo(cfg.actor_repo)
         .blocklist_repo(cfg.blocklist_repo)
-        .user_repo(user_repo)
+        .user_repo(cfg.user_repo)
         .content_reader(cfg.ap_handler.clone())
         .object_handler(cfg.ap_handler)
         .allow_registration(cfg.allow_registration)
         .software_name("thoughts")
         .debug(cfg.debug)
-        .signed_fetch_actor_id(instance_actor::INSTANCE_ACTOR_ID);
+        .signed_fetch_actor_id(INSTANCE_ACTOR_ID);
     if let Some(publisher) = cfg.event_publisher {
         builder = builder.event_publisher(publisher);
     }

crates/adapters/postgres/migrations/022_instance_actor.sql

@@ -0,0 +1,10 @@
+INSERT INTO users (id, username, email, password_hash, display_name, bio)
+VALUES (
+    '00000000-0000-4000-8000-000000000000',
+    'instance',
+    'noreply@instance.invalid',
+    '!service-actor-no-login',
+    NULL,
+    NULL
+)
+ON CONFLICT (id) DO NOTHING;