Add modular app structure for L2 server

- Create app factory with routers and templates
- Auth, assets, activities, anchors, storage, users, renderers routers
- Federation router for WebFinger and nodeinfo
- Jinja2 templates for L2 pages
- Config and dependency injection

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

app/routers/users.py

@@ -0,0 +1,161 @@
+"""
+User profile routes for L2 server.
+
+Handles ActivityPub actor profiles.
+"""
+
+import logging
+
+from fastapi import APIRouter, Request, HTTPException
+from fastapi.responses import JSONResponse
+
+from artdag_common import render
+from artdag_common.middleware import wants_html
+
+from ..config import settings
+from ..dependencies import get_templates, get_user_from_cookie
+
+router = APIRouter()
+logger = logging.getLogger(__name__)
+
+
+@router.get("/users/{username}")
+async def get_user_profile(
+    username: str,
+    request: Request,
+):
+    """Get user profile (ActivityPub actor)."""
+    import db
+
+    user = await db.get_user(username)
+    if not user:
+        raise HTTPException(404, "User not found")
+
+    # ActivityPub response
+    accept = request.headers.get("accept", "")
+    if "application/activity+json" in accept or "application/ld+json" in accept:
+        actor = {
+            "@context": [
+                "https://www.w3.org/ns/activitystreams",
+                "https://w3id.org/security/v1",
+            ],
+            "type": "Person",
+            "id": f"https://{settings.domain}/users/{username}",
+            "name": user.get("display_name", username),
+            "preferredUsername": username,
+            "inbox": f"https://{settings.domain}/users/{username}/inbox",
+            "outbox": f"https://{settings.domain}/users/{username}/outbox",
+            "publicKey": {
+                "id": f"https://{settings.domain}/users/{username}#main-key",
+                "owner": f"https://{settings.domain}/users/{username}",
+                "publicKeyPem": user.get("public_key", ""),
+            },
+        }
+        return JSONResponse(content=actor, media_type="application/activity+json")
+
+    # HTML profile page
+    current_user = get_user_from_cookie(request)
+    assets = await db.get_user_assets(username, limit=12)
+
+    templates = get_templates(request)
+    return render(templates, "users/profile.html", request,
+        profile=user,
+        assets=assets,
+        user={"username": current_user} if current_user else None,
+    )
+
+
+@router.get("/users/{username}/outbox")
+async def get_outbox(
+    username: str,
+    request: Request,
+    page: bool = False,
+):
+    """Get user's outbox (ActivityPub)."""
+    import db
+
+    user = await db.get_user(username)
+    if not user:
+        raise HTTPException(404, "User not found")
+
+    actor_id = f"https://{settings.domain}/users/{username}"
+
+    if not page:
+        # Return collection summary
+        total = await db.count_user_activities(username)
+        return JSONResponse(
+            content={
+                "@context": "https://www.w3.org/ns/activitystreams",
+                "type": "OrderedCollection",
+                "id": f"{actor_id}/outbox",
+                "totalItems": total,
+                "first": f"{actor_id}/outbox?page=true",
+            },
+            media_type="application/activity+json",
+        )
+
+    # Return paginated activities
+    activities = await db.get_user_activities(username, limit=20)
+    items = [a.get("activity_json", a) for a in activities]
+
+    return JSONResponse(
+        content={
+            "@context": "https://www.w3.org/ns/activitystreams",
+            "type": "OrderedCollectionPage",
+            "id": f"{actor_id}/outbox?page=true",
+            "partOf": f"{actor_id}/outbox",
+            "orderedItems": items,
+        },
+        media_type="application/activity+json",
+    )
+
+
+@router.post("/users/{username}/inbox")
+async def receive_inbox(
+    username: str,
+    request: Request,
+):
+    """Receive ActivityPub inbox message."""
+    import db
+
+    user = await db.get_user(username)
+    if not user:
+        raise HTTPException(404, "User not found")
+
+    # TODO: Verify HTTP signature
+    # TODO: Process activity (Follow, Like, Announce, etc.)
+
+    body = await request.json()
+    logger.info(f"Received inbox activity for {username}: {body.get('type')}")
+
+    # For now, just acknowledge
+    return {"status": "accepted"}
+
+
+@router.get("/")
+async def home(request: Request):
+    """Home page."""
+    import db
+    import markdown
+
+    username = get_user_from_cookie(request)
+
+    # Get recent activities
+    activities = await db.get_activities(limit=10)
+
+    # Get README if exists
+    readme_html = ""
+    try:
+        from pathlib import Path
+        readme_path = Path(__file__).parent.parent.parent / "README.md"
+        if readme_path.exists():
+            readme_html = markdown.markdown(readme_path.read_text())
+    except Exception:
+        pass
+
+    templates = get_templates(request)
+    return render(templates, "home.html", request,
+        user={"username": username} if username else None,
+        activities=activities,
+        readme_html=readme_html,
+    )