remove the dead multi-user surface

Officer is single-user: the server owner is the only account, created once by
/auth/bootstrap. Everything that existed to serve additional users was
unreachable, so it is gone rather than left looking like it does something.

Accounts: drop the invite / resend-invite / delete / list-users routes and the
Users settings screen, the inert /auth/signup handler, and the account
verification chain it fed (verify, resend-verification, VerifyScreen, the
UserInvite + VerifyAdmin + VerifyRegistration templates). /auth/verify-token
survives for password resets only, and now requires a reset-password token
rather than accepting any signed JWT.

Roles: drop the users.role column and the four-value USER_ROLES enum. The
permissions table granted every role identical methods, and every
role === 'Super Admin' check was permanently true. The JWT no longer carries a
role claim.

Sandbox: remove sidecar/sandbox.ts and its five call sites. bwrap was selected
only for non-Super-Admin users, so it never ran. It was also not a usable agent
jail as written — --share-net, the project root (with .env) bound read-only,
and runuser dropping to the server's own uid. Rebuilding it for agent
containment would be a different construction, and git history keeps this one.

getHomeDir keeps its DATA_PATH meaning; the new getOwnerHomeDir resolves the
owner's real login home, which is what terminals, chats and task runs use.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

src/servers/channels/send-and-await.ts

@@ -13,7 +13,6 @@ type SendAndAwaitParams = {
   context: string;
   contextId: string;
   model?: string;
-  role?: string;
 };
 
 type SendAndAwaitResult = {
@@ -83,7 +82,6 @@ export async function sendAndAwait(params: SendAndAwaitParams): Promise<SendAndA
       prompt: params.prompt,
       sessionKey: sessionId,
       model,
-      role: params.role,
     });
   } finally {
     releaseLock!();