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/store/memory_store.py

@@ -0,0 +1,34 @@
+"""
+Memory store — SQLite-backed persistence for cross-session memory.
+Only active when a session is created with memory: new or memory: inherit:<token>.
+"""
+
+import logging
+from typing import Optional
+
+import aiosqlite
+
+logger = logging.getLogger(__name__)
+
+DB_PATH = "fellowship_memory.db"
+
+
+class MemoryStore:
+    def __init__(self, db_path: str = DB_PATH) -> None:
+        self.db_path = db_path
+
+    async def init(self) -> None:
+        """Create tables if they don't exist. Call once at startup."""
+        raise NotImplementedError
+
+    async def save(self, session_token: str, memory: str) -> None:
+        """Persist a memory string for the given session token."""
+        raise NotImplementedError
+
+    async def load(self, session_token: str) -> Optional[str]:
+        """Load the stored memory for the given session token, or None if absent."""
+        raise NotImplementedError
+
+    async def delete(self, session_token: str) -> None:
+        """Delete memory for a session."""
+        raise NotImplementedError