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/core/queue.py

@@ -0,0 +1,43 @@
+"""
+Talker message queue — holds incoming talker messages in arrival order.
+The session loop drains this queue one message at a time.
+"""
+
+import asyncio
+import logging
+from dataclasses import dataclass
+
+logger = logging.getLogger(__name__)
+
+
+@dataclass
+class QueuedMessage:
+    talker_id: str
+    talker_name: str
+    content: str
+
+
+class MessageQueue:
+    def __init__(self) -> None:
+        self._queue: asyncio.Queue[QueuedMessage] = asyncio.Queue()
+
+    def enqueue(self, message: QueuedMessage) -> None:
+        """Add a talker message to the queue. Non-blocking."""
+        self._queue.put_nowait(message)
+
+    async def dequeue(self) -> QueuedMessage:
+        """Wait for and return the next message. Blocks until one is available."""
+        return await self._queue.get()
+
+    def dequeue_nowait(self) -> QueuedMessage | None:
+        """Return the next message without waiting, or None if the queue is empty."""
+        try:
+            return self._queue.get_nowait()
+        except asyncio.QueueEmpty:
+            return None
+
+    def is_empty(self) -> bool:
+        return self._queue.empty()
+
+    def size(self) -> int:
+        return self._queue.qsize()