fix: remove actor/followers/following routes from router()

These paths need content negotiation in real apps (AP JSON vs UI JSON).
k-ap can't serve the UI half, so the consuming app owns the route and
calls actor_json/followers_collection_json/following_collection_json
to produce the AP response.

The route conflict caused a panic when thoughts mounted its own
/users/{username}/... routes alongside service.router().

router() now registers only what k-ap fully owns:
- POST /inbox, POST /users/{id}/inbox (signature verification)
- GET /users/{id}/outbox
- GET /users/{id}/featured
- GET /.well-known/webfinger, nodeinfo, /nodeinfo/2.0

CHANGELOG.md

@@ -86,6 +86,8 @@ service.broadcast_create_note(user_id, note_json, ApVisibility::Public, mentione
 
 **`GET /users/{id}/featured` route** — serves an `OrderedCollection` of pinned posts via `ApContentReader::get_featured_objects`. Default is an empty collection.
 
+**`router()` no longer registers `GET /users/{id}`, `/followers`, or `/following`** — these paths need content negotiation (AP JSON vs UI JSON) which k-ap can't do. Your application owns those routes and calls `actor_json`, `followers_collection_json`, `following_collection_json` to produce the AP response. See README for the pattern.
+
 **`FederationEvent::BackfillRequested`** — when an `EventPublisher` is configured, `accept_follower` publishes this event instead of spawning an in-process task. Process it by calling `run_backfill_for_follower`.
 
 **`run_backfill_for_follower(owner_user_id, follower_inbox_url)`** — public method for workers processing `BackfillRequested` events.

README.md

@@ -67,19 +67,37 @@ let router = Router::new().merge(service.router());
 
 ## What the service handles for you
 
+`service.router()` registers only the routes k-ap fully owns:
+
 | Route | Description |
 |-------|-------------|
-| `GET /users/{id}` | AP actor JSON with public key and security `@context` |
-| `POST /users/{id}/inbox` | Per-user inbox — verifies HTTP signatures, 1 MB limit |
-| `POST /inbox` | Shared inbox — same verification |
+| `POST /inbox` | Shared inbox — HTTP signature verification + dispatch, 1 MB limit |
+| `POST /users/{id}/inbox` | Per-user inbox — same |
 | `GET /users/{id}/outbox` | Cursor-based `OrderedCollection` |
-| `GET /users/{id}/followers` | Offset-paginated follower collection |
-| `GET /users/{id}/following` | Offset-paginated following collection |
-| `GET /users/{id}/featured` | Pinned posts `OrderedCollection` (from `get_featured_objects`) |
+| `GET /users/{id}/featured` | Pinned posts `OrderedCollection` |
 | `GET /.well-known/webfinger` | JRD with `aliases` field |
 | `GET /.well-known/nodeinfo` | NodeInfo well-known redirect |
 | `GET /nodeinfo/2.0` | NodeInfo 2.0 |
 
+**Not registered by `router()`:** `GET /users/{id}`, `GET /users/{id}/followers`, `GET /users/{id}/following`.
+
+These paths are dual-purpose in real applications — they must serve both AP JSON (`application/activity+json`) and the app's own UI JSON (content negotiation). k-ap can't do the UI half, so your application owns the route and calls k-ap's helper methods to produce the AP response:
+
+```rust
+// In your axum actor handler — serve AP JSON or UI JSON based on Accept header
+async fn actor_handler(Path(username): Path<String>, headers: HeaderMap, ...) {
+    if wants_ap_json(&headers) {
+        let json = service.actor_json(&user.id.to_string()).await?;
+        return ap_json_response(json);
+    }
+    // ... serve UI response
+}
+
+// Similarly for followers/following:
+let json = service.followers_collection_json(user_id, page).await?;
+let json = service.following_collection_json(user_id, page).await?;
+```
+
 ## ApUser fields
 
 Your `ApUserRepository` returns `ApUser`. All fields control how the actor is serialized:

src/service/mod.rs

@@ -5,13 +5,11 @@ use axum::{Router, extract::DefaultBodyLimit, routing::get, routing::post};
 use url::Url;
 
 use crate::{
-    actor_handler::actor_handler,
     actors::{DbActor, get_local_actor},
     content::{ApContentReader, ApObjectHandler},
     data::FederationData,
     featured_handler::featured_handler,
     federation::ApFederationConfig,
-    followers_handler::{followers_handler, following_handler},
     inbox::inbox_handler,
     nodeinfo::{nodeinfo_handler, nodeinfo_well_known_handler},
     outbox::outbox_handler,
@@ -190,7 +188,19 @@ impl ActivityPubService {
         &self.base_url
     }
 
-    /// Returns the ActivityPub router. Inbox routes enforce a 1 MB body limit.
+    /// Returns the ActivityPub router.
+    ///
+    /// Registers only routes that k-ap fully owns:
+    /// - `POST /inbox` + `POST /users/{id}/inbox` — signature verification + dispatch (1 MB limit)
+    /// - `GET /users/{id}/outbox` — cursor-paginated OrderedCollection
+    /// - `GET /users/{id}/featured` — pinned posts OrderedCollection
+    /// - `GET /.well-known/webfinger`, `GET /.well-known/nodeinfo`, `GET /nodeinfo/2.0`
+    ///
+    /// **Not registered:** `GET /users/{id}`, `GET /users/{id}/followers`,
+    /// `GET /users/{id}/following`. Real applications need those paths to serve
+    /// both AP JSON and their own UI JSON (content negotiation), so they must own
+    /// the route. Call `actor_json`, `followers_collection_json`, and
+    /// `following_collection_json` from your own handler to produce the AP response.
     pub fn router<S>(&self) -> Router<S>
     where
         S: Clone + Send + Sync + 'static,
@@ -203,14 +213,11 @@ impl ActivityPubService {
                 "/inbox",
                 post(inbox_handler).layer(DefaultBodyLimit::max(1024 * 1024)),
             )
-            .route("/users/{id}", get(actor_handler))
             .route(
                 "/users/{id}/inbox",
                 post(inbox_handler).layer(DefaultBodyLimit::max(1024 * 1024)),
             )
             .route("/users/{id}/outbox", get(outbox_handler))
-            .route("/users/{id}/followers", get(followers_handler))
-            .route("/users/{id}/following", get(following_handler))
             .route("/users/{id}/featured", get(featured_handler))
             .layer(self.federation_config.middleware())
     }