Add per-app ActivityPub actors via shared AP blueprint

Each AP-enabled app (blog, market, events, federation) now serves its
own webfinger, actor profile, inbox, outbox, and followers endpoints.
Per-app actors are virtual projections of the same ActorProfile/keypair,
scoped by APFollower.app_domain and APActivity.origin_app.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

services/federation_impl.py

@@ -75,6 +75,7 @@ def _follower_to_dto(f: APFollower) -> APFollowerDTO:
         follower_inbox=f.follower_inbox,
         follower_actor_url=f.follower_actor_url,
         created_at=f.created_at,
+        app_domain=f.app_domain,
     )
 
 
@@ -252,6 +253,7 @@ class SqlFederationService:
     async def get_outbox(
         self, session: AsyncSession, username: str,
         page: int = 1, per_page: int = 20,
+        origin_app: str | None = None,
     ) -> tuple[list[APActivityDTO], int]:
         actor = (
             await session.execute(
@@ -261,22 +263,23 @@ class SqlFederationService:
         if actor is None:
             return [], 0
 
+        filters = [
+            APActivity.actor_profile_id == actor.id,
+            APActivity.is_local == True,  # noqa: E712
+        ]
+        if origin_app is not None:
+            filters.append(APActivity.origin_app == origin_app)
+
         total = (
             await session.execute(
-                select(func.count(APActivity.id)).where(
-                    APActivity.actor_profile_id == actor.id,
-                    APActivity.is_local == True,  # noqa: E712
-                )
+                select(func.count(APActivity.id)).where(*filters)
             )
         ).scalar() or 0
 
         offset = (page - 1) * per_page
         result = await session.execute(
             select(APActivity)
-            .where(
-                APActivity.actor_profile_id == actor.id,
-                APActivity.is_local == True,  # noqa: E712
-            )
+            .where(*filters)
             .order_by(APActivity.published.desc())
             .limit(per_page)
             .offset(offset)
@@ -315,6 +318,7 @@ class SqlFederationService:
 
     async def get_followers(
         self, session: AsyncSession, username: str,
+        app_domain: str | None = None,
     ) -> list[APFollowerDTO]:
         actor = (
             await session.execute(
@@ -324,15 +328,18 @@ class SqlFederationService:
         if actor is None:
             return []
 
-        result = await session.execute(
-            select(APFollower).where(APFollower.actor_profile_id == actor.id)
-        )
+        q = select(APFollower).where(APFollower.actor_profile_id == actor.id)
+        if app_domain is not None:
+            q = q.where(APFollower.app_domain == app_domain)
+
+        result = await session.execute(q)
         return [_follower_to_dto(f) for f in result.scalars().all()]
 
     async def add_follower(
         self, session: AsyncSession, username: str,
         follower_acct: str, follower_inbox: str, follower_actor_url: str,
         follower_public_key: str | None = None,
+        app_domain: str | None = None,
     ) -> APFollowerDTO:
         actor = (
             await session.execute(
@@ -342,15 +349,17 @@ class SqlFederationService:
         if actor is None:
             raise ValueError(f"Actor not found: {username}")
 
-        # Upsert: update if already following, insert if new
-        existing = (
-            await session.execute(
-                select(APFollower).where(
-                    APFollower.actor_profile_id == actor.id,
-                    APFollower.follower_acct == follower_acct,
-                )
-            )
-        ).scalar_one_or_none()
+        # Upsert: update if already following this (actor, acct, app_domain)
+        q = select(APFollower).where(
+            APFollower.actor_profile_id == actor.id,
+            APFollower.follower_acct == follower_acct,
+        )
+        if app_domain is not None:
+            q = q.where(APFollower.app_domain == app_domain)
+        else:
+            q = q.where(APFollower.app_domain.is_(None))
+
+        existing = (await session.execute(q)).scalar_one_or_none()
 
         if existing:
             existing.follower_inbox = follower_inbox
@@ -365,6 +374,7 @@ class SqlFederationService:
             follower_inbox=follower_inbox,
             follower_actor_url=follower_actor_url,
             follower_public_key=follower_public_key,
+            app_domain=app_domain,
         )
         session.add(follower)
         await session.flush()
@@ -372,6 +382,7 @@ class SqlFederationService:
 
     async def remove_follower(
         self, session: AsyncSession, username: str, follower_acct: str,
+        app_domain: str | None = None,
     ) -> bool:
         actor = (
             await session.execute(
@@ -381,12 +392,16 @@ class SqlFederationService:
         if actor is None:
             return False
 
-        result = await session.execute(
-            delete(APFollower).where(
-                APFollower.actor_profile_id == actor.id,
-                APFollower.follower_acct == follower_acct,
-            )
-        )
+        filters = [
+            APFollower.actor_profile_id == actor.id,
+            APFollower.follower_acct == follower_acct,
+        ]
+        if app_domain is not None:
+            filters.append(APFollower.app_domain == app_domain)
+        else:
+            filters.append(APFollower.app_domain.is_(None))
+
+        result = await session.execute(delete(APFollower).where(*filters))
         return result.rowcount > 0
 
     async def get_followers_paginated(