fix: Resolve API/state type mismatch in users.ts authMecs

[BillyOutlast]

Problem

server/composables/users.ts has a @ts-expect-error suppressing a type mismatch between the API response and the shared state type.

Current state:

export const fetchUsers = async () => {
  const users = useUsers();
  const newValue = await $dropFetch("/api/v1/admin/users");
  // @ts-expect-error: API returns authMecs without `id`, but state type requires it
  users.value = newValue;
  return newValue;
};

The useUsers() state type requires authMecs entries with { id: string; mec: AuthMec }, but the /api/v1/admin/users API response intentionally omits id.

Impact

• Every useUsers() consumer is exposed to missing runtime data
• The @ts-expect-error hides a real incompatibility
• Type safety is compromised for the admin users feature

Proposed Solutions

Option A (recommended): Normalize the API response by generating/assigning id during fetchUsers before storing in state.

Option B: Update the shared state type and all consumers to match the actual API payload (without id).

Option C: Update the API endpoint to include id in the response.

Context

• Identified during PR remediation: Phase 1-4 fixes (16 items) #45 code review (CodeRabbit comment)
• File: server/composables/users.ts:22-24
• Related API: /api/v1/admin/users

Acceptance Criteria

• @ts-expect-error removed from fetchUsers
• Type check passes without suppression
• All useUsers() consumers work correctly with the resolved type