Roles, part 3b: a member cannot change another account or the crew's standing instructions #2385

Part of #2303.

Done looks like:

• [ ] Changing another account (its profile, password, role or tokens) and editing the crew's standing instructions refuse a member with 403 on the API and a plain line on the page. A member can still change their own account.
• [ ] Tests: a member is refused for each act, still changes their own account, and an admin succeeds.

Parked by the crew: the check failed ("quotas > a non-admin is refused") and the decider saw no point in another try (pull #2399 closed). Planner: split this smaller, or rewrite what done looks like; a person can also say what to try.

Parked by the crew: the check failed ("accounts: the owner sees, suspends and removes > nobody but the owner sees the list, or can act on it") and the decider saw no point in another try (pull #2412 closed).

Parked twice since a person last spoke here, so it is the planner's now. Every reason:

1. the check failed ("quotas > a non-admin is refused") and the decider saw no point in another try (pull #2399 closed)
2. the check failed ("accounts: the owner sees, suspends and removes > nobody but the owner sees the list, or can act on it") and the decider saw no point in another try (pull #2412 closed)

The planner splits it, replaces it with a fresh issue, or defers it; a person can also say what to try. Nothing starts here until then, and the board lists it.

Split into #2421 (other accounts) and #2422 (standing instructions). Both tries invented a new refusal and broke the suites asserting the existing one (test/quotas.test.ts, test/accounts.test.ts). The new issues reuse that refusal and must leave both suites unchanged.