Add missing /api/auth/me endpoint to admin server

The /api/auth/me endpoint was never added after the admin server was
split from the main server. Without it, auth tokens couldn't be validated
against the admin server — the SPA catch-all would serve the frontend instead.

admin_server.py

@@ -804,6 +804,27 @@ def login(body: dict):
     return result
 
 
+# ─── Auth: Me (validate token) ───────────────────────────────────────────────
+
+
+@app.get("/api/auth/me")
+def auth_me(request: Request):
+    """Return the current authenticated user from the Authorization header."""
+    auth_header = request.headers.get("Authorization", "")
+    if not auth_header.startswith("Bearer "):
+        raise HTTPException(status_code=401, detail="Missing or invalid Authorization header")
+    token = auth_header[7:]
+    conn = get_db()
+    row = conn.execute(
+        "SELECT u.* FROM users u JOIN sessions s ON u.id = s.user_id WHERE s.token = ? AND s.expires_at > datetime('now')",
+        (token,),
+    ).fetchone()
+    conn.close()
+    if row is None:
+        raise HTTPException(status_code=401, detail="Invalid or expired token")
+    return _user_to_dict(row)
+
+
 # ─── Customers API ──────────────────────────────────────────────────────────