feat: replace instance actor decorator with real DB row

Migrations (postgres + sqlite) insert a service actor with a well-known
UUID. Removes the InstanceActorUserRepo wrapper.

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

@@ -1,7 +1,6 @@
 pub mod composite_handler;
 pub mod event_handler;
 pub mod federation_event_bridge;
-pub mod instance_actor;
 pub mod objects;
 pub mod port;
 pub mod remote_review_repository;
@@ -10,6 +9,9 @@ pub(crate) mod urls;
 pub mod user_adapter;
 pub mod watchlist_handler;
 
+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]);
+
 // Re-export the generic base types that callers need
 pub use k_ap::{
     ActivityPubService, ActivityRepository, ActorRepository, ApContentReader, ApFederationConfig,
@@ -97,18 +99,17 @@ pub async fn wire(deps: ActivityPubDeps) -> anyhow::Result<ActivityPubWire> {
         federation_event_bridge::FederationEventBridge::new(event_publisher),
     );
 
-    let user_repo = std::sync::Arc::new(instance_actor::InstanceActorUserRepo::new(
-        std::sync::Arc::new(DomainUserRepoAdapter::new(user_repo, base_url.clone())),
-        base_url.clone(),
-    ));
     let concrete = std::sync::Arc::new(
         ActivityPubService::builder(base_url.clone())
             .activity_repo(activity_repo)
             .follow_repo(follow_repo)
             .actor_repo(actor_repo)
             .blocklist_repo(blocklist_repo)
-            .user_repo(user_repo)
+            .user_repo(std::sync::Arc::new(DomainUserRepoAdapter::new(
-            .signed_fetch_actor_id(instance_actor::INSTANCE_ACTOR_ID)
+                user_repo,
+                base_url.clone(),
+            )))
+            .signed_fetch_actor_id(INSTANCE_ACTOR_ID)
             .content_reader(composite.clone() as std::sync::Arc<dyn ApContentReader>)
             .object_handler(composite as std::sync::Arc<dyn ApObjectHandler>)
             .event_publisher(fed_event_bridge)

crates/adapters/postgres/migrations/0022_instance_actor.sql

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

crates/adapters/sqlite/migrations/0022_instance_actor.sql

@@ -0,0 +1,8 @@
+INSERT OR IGNORE INTO users (id, email, password_hash, created_at, username)
+VALUES (
+    '00000000-0000-4000-8000-000000000000',
+    'noreply@instance.invalid',
+    '!service-actor-no-login',
+    datetime('now'),
+    'instance'
+);