Initial project structure

Scaffold all modules, route stubs, data models, and config.
No logic implemented yet — all core methods raise NotImplementedError.
Establishes the full directory layout matching the architecture in CLAUDE.md.

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

fellowship/api/routes/sessions.py

@@ -0,0 +1,94 @@
+"""
+Session API routes. Route handlers are thin — they validate input and delegate to core/.
+All routes are mounted under /v1 in main.py.
+"""
+
+import logging
+
+from fastapi import APIRouter, HTTPException, WebSocket, WebSocketDisconnect
+from fastapi.responses import StreamingResponse
+
+from fellowship.api.models.session import (
+    CreateSessionRequest,
+    CreateSessionResponse,
+    SessionStatusResponse,
+)
+
+logger = logging.getLogger(__name__)
+
+router = APIRouter(tags=["sessions"])
+
+
+@router.post(
+    "/session/create",
+    response_model=CreateSessionResponse,
+    summary="Initialize a new session",
+    description="Create a new Fellowship session with the given bots and options. Returns a session token.",
+)
+async def create_session(body: CreateSessionRequest) -> CreateSessionResponse:
+    raise NotImplementedError
+
+
+@router.get(
+    "/session/{token}",
+    response_model=SessionStatusResponse,
+    summary="Get session status",
+    description="Returns current state, turn count, and connected member counts for a session.",
+)
+async def get_session(token: str) -> SessionStatusResponse:
+    raise NotImplementedError
+
+
+@router.delete(
+    "/session/{token}",
+    summary="End a session",
+    description="Terminates the session loop and disconnects all members.",
+)
+async def end_session(token: str) -> dict[str, str]:
+    raise NotImplementedError
+
+
+@router.post(
+    "/session/{token}/pause",
+    summary="Pause a session",
+    description="Halts the session loop. Members remain connected and receive a session_paused event.",
+)
+async def pause_session(token: str) -> dict[str, str]:
+    raise NotImplementedError
+
+
+@router.post(
+    "/session/{token}/resume",
+    summary="Resume a paused session",
+    description="Restarts the session loop. Members receive a session_resumed event.",
+)
+async def resume_session(token: str) -> dict[str, str]:
+    raise NotImplementedError
+
+
+@router.get(
+    "/session/{token}/history",
+    summary="Get full conversation history",
+    description="Returns the complete ordered message log for the session.",
+)
+async def get_history(token: str) -> dict:
+    raise NotImplementedError
+
+
+@router.websocket("/session/{token}/connect")
+async def websocket_connect(websocket: WebSocket, token: str, role: str = "observer") -> None:
+    """
+    WebSocket connection for talkers (role=talker) and observers (role=observer).
+    On connect: sends a history event with the full conversation, then streams live events.
+    Talkers may send user_message and ping frames.
+    """
+    raise NotImplementedError
+
+
+@router.get(
+    "/session/{token}/stream",
+    summary="SSE observe-only stream",
+    description="Server-Sent Events stream for observers. Sends history replay then live events.",
+)
+async def sse_stream(token: str) -> StreamingResponse:
+    raise NotImplementedError