some basic statistics and invite tree, plus watch new data

bincio/serve/db.py

@@ -154,6 +154,33 @@ def delete_user(db: sqlite3.Connection, handle: str) -> None:
     db.commit()
 
 
+def get_member_tree(db: sqlite3.Connection) -> list[dict]:
+    """Return users with their inviter handle and join timestamp.
+
+    Each entry: {handle, display_name, created_at, invited_by (handle or None)}.
+    Ordered oldest-first so callers can build the tree top-down.
+    """
+    users = {r["handle"]: r for r in db.execute(
+        "SELECT handle, display_name, created_at FROM users ORDER BY created_at"
+    ).fetchall()}
+    # Map invitee → inviter from the used invites
+    invited_by: dict[str, str] = {}
+    for row in db.execute(
+        "SELECT created_by, used_by FROM invites WHERE used_by IS NOT NULL"
+    ).fetchall():
+        invited_by[row["used_by"]] = row["created_by"]
+
+    return [
+        {
+            "handle": r["handle"],
+            "display_name": r["display_name"],
+            "created_at": r["created_at"],
+            "invited_by": invited_by.get(r["handle"]),
+        }
+        for r in users.values()
+    ]
+
+
 def count_users(db: sqlite3.Connection) -> int:
     """Return the total number of registered users."""
     row = db.execute("SELECT COUNT(*) FROM users").fetchone()