feat(activitypub): index hashtags from incoming federated notes

- accept_note now returns ThoughtId (INSERT then SELECT by ap_id)
- ThoughtsObjectHandler extracts Hashtag entries from AP tag array, strips #, lowercases
- Calls TagRepository.find_or_create + attach_to_thought for each tag; failures silenced
- TagRepository injected into handler via bootstrap and worker factories

crates/adapters/activitypub-base/src/ap_ports.rs

@@ -72,7 +72,7 @@ pub trait ActivityPubRepository: Send + Sync {
         content_warning: Option<String>,
         visibility: &str,
         in_reply_to: Option<&str>,
-    ) -> Result<(), DomainError>;
+    ) -> Result<ThoughtId, DomainError>;
 
     /// Apply an Update to a previously accepted remote Note.
     async fn apply_note_update(&self, ap_id: &str, new_content: &str) -> Result<(), DomainError>;

crates/adapters/activitypub/src/handler.rs

@@ -10,13 +10,14 @@ use url::Url;
 use crate::note::ThoughtNote;
 use crate::urls::ThoughtsUrls;
 use activitypub_base::{ActivityPubRepository, ApObjectHandler};
-use domain::ports::EventPublisher;
+use domain::ports::{EventPublisher, TagRepository};
 use domain::value_objects::UserId;
 
 pub struct ThoughtsObjectHandler {
     repo: Arc<dyn ActivityPubRepository>,
     urls: ThoughtsUrls,
     event_publisher: Option<Arc<dyn EventPublisher>>,
+    tag_repo: Arc<dyn TagRepository>,
 }
 
 impl ThoughtsObjectHandler {
@@ -24,11 +25,13 @@ impl ThoughtsObjectHandler {
         repo: Arc<dyn ActivityPubRepository>,
         base_url: &str,
         event_publisher: Option<Arc<dyn EventPublisher>>,
+        tag_repo: Arc<dyn TagRepository>,
     ) -> Self {
         Self {
             repo,
             urls: ThoughtsUrls::new(base_url),
             event_publisher,
+            tag_repo,
         }
     }
 }
@@ -138,7 +141,7 @@ impl ApObjectHandler for ThoughtsObjectHandler {
             "direct"
         };
 
-        self.repo
+        let thought_id = self.repo
             .accept_note(
                 ap_id.as_str(),
                 &author_id,
@@ -152,6 +155,22 @@ impl ApObjectHandler for ThoughtsObjectHandler {
             .await
             .map_err(|e| anyhow!("{e}"))?;
 
+        // Extract and index hashtags from the AP tag array.
+        let hashtag_names: Vec<String> = note
+            .tag
+            .iter()
+            .filter(|t| t.get("type").and_then(|v| v.as_str()) == Some("Hashtag"))
+            .filter_map(|t| t.get("name").and_then(|v| v.as_str()))
+            .map(|name| name.trim_start_matches('#').to_lowercase())
+            .filter(|name| !name.is_empty())
+            .collect();
+
+        for name in hashtag_names {
+            if let Ok(tag) = self.tag_repo.find_or_create(&name).await {
+                let _ = self.tag_repo.attach_to_thought(&thought_id, tag.id).await;
+            }
+        }
+
         // Fire mention notifications for local @mentions in the note's tag array.
         let base_url = url::Url::parse(&self.urls.base_url)
             .ok()

crates/adapters/postgres/src/activitypub.rs

@@ -220,7 +220,7 @@ impl ActivityPubRepository for PgActivityPubRepository {
         content_warning: Option<String>,
         visibility: &str,
         in_reply_to: Option<&str>,
-    ) -> Result<(), DomainError> {
+    ) -> Result<ThoughtId, DomainError> {
         let capped: String = content.chars().take(MAX_REMOTE_CONTENT_CHARS).collect();
         let (in_reply_to_id, in_reply_to_url) = match in_reply_to {
             Some(url) => {
@@ -251,8 +251,16 @@ impl ActivityPubRepository for PgActivityPubRepository {
         .bind(&in_reply_to_url)
         .execute(&self.pool)
         .await
-        .into_domain()
-        .map(|_| ())
+        .into_domain()?;
+
+        // SELECT the id — works whether the INSERT was a no-op or not (idempotent).
+        let row: (uuid::Uuid,) =
+            sqlx::query_as("SELECT id FROM thoughts WHERE ap_id=$1")
+                .bind(ap_id)
+                .fetch_one(&self.pool)
+                .await
+                .into_domain()?;
+        Ok(ThoughtId::from_uuid(row.0))
     }
 
     async fn apply_note_update(&self, ap_id: &str, new_content: &str) -> Result<(), DomainError> {
@@ -365,4 +373,34 @@ mod tests {
         let repo = PgActivityPubRepository::new(pool);
         assert_eq!(repo.count_local_notes().await.unwrap(), 0);
     }
+
+    #[sqlx::test(migrations = "./migrations")]
+    async fn accept_note_returns_thought_id(pool: sqlx::PgPool) {
+        let repo = PgActivityPubRepository::new(pool.clone());
+        let actor_user_id = repo
+            .intern_remote_actor("https://remote.example/users/alice")
+            .await
+            .unwrap();
+
+        let thought_id = repo
+            .accept_note(
+                "https://remote.example/notes/1",
+                &actor_user_id,
+                "Hello #rust world",
+                chrono::Utc::now(),
+                false,
+                None,
+                "public",
+                None,
+            )
+            .await
+            .unwrap();
+
+        let row: (uuid::Uuid,) = sqlx::query_as("SELECT id FROM thoughts WHERE ap_id=$1")
+            .bind("https://remote.example/notes/1")
+            .fetch_one(&pool)
+            .await
+            .unwrap();
+        assert_eq!(thought_id.as_uuid(), row.0);
+    }
 }

crates/application/src/testing.rs

@@ -103,8 +103,8 @@ impl ActivityPubRepository for TestApRepo {
         _content_warning: Option<String>,
         _visibility: &str,
         _in_reply_to: Option<&str>,
-    ) -> Result<(), DomainError> {
-        Ok(())
+    ) -> Result<ThoughtId, DomainError> {
+        Ok(ThoughtId::from_uuid(uuid::Uuid::new_v4()))
     }
     async fn apply_note_update(
         &self,

crates/bootstrap/src/factory.rs

@@ -77,6 +77,7 @@ pub async fn build(cfg: &Config) -> Infrastructure {
                 Arc::new(PgActivityPubRepository::new(pool.clone())),
                 &cfg.base_url,
                 Some(event_publisher.clone()),
+                Arc::new(postgres::tag::PgTagRepository::new(pool.clone())),
             )),
             cfg.base_url.clone(),
             cfg.allow_registration,

crates/presentation/src/testing.rs

@@ -76,8 +76,8 @@ impl ActivityPubRepository for NoOpApRepo {
         _content_warning: Option<String>,
         _visibility: &str,
         _in_reply_to: Option<&str>,
-    ) -> Result<(), DomainError> {
-        Ok(())
+    ) -> Result<ThoughtId, DomainError> {
+        Ok(ThoughtId::from_uuid(uuid::Uuid::new_v4()))
     }
     async fn apply_note_update(
         &self,

crates/worker/src/factory.rs

@@ -49,6 +49,7 @@ pub async fn build(database_url: &str, base_url: &str, nats_url: &str) -> Worker
                 Arc::new(PgActivityPubRepository::new(pool.clone())),
                 base_url,
                 None,
+                Arc::new(postgres::tag::PgTagRepository::new(pool.clone())),
             )),
             base_url.to_string(),
             false,