refactor: extract typed boolean-flag storage accessors

[Jagadeeshftw]

Summary

Pure refactor — behaviour is byte-for-byte identical. Adds two private free functions, read_flag (centralising the unwrap_or(false) default) and write_flag, and routes every persistent boolean read/write through them: the Paused checks in record_usage/settle; the RequireServiceRegistration/ServiceRegistered/ServiceDisabled/AllowlistEnabled/AgentAllowed reads in record_usage; the bool getters; and the bool writes in set_allowlist_enabled, set_agent_allowed, set_require_service_registration, register_service, pause/unpause, and set_service_disabled. u32/i128/u64 slots (including the u32::MAX-defaulting MaxRequestsPerCall) are untouched, and the ordering of checks is preserved.

Closes #47

Test output

test result: ok. 24 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out

Security notes

Centralising unwrap_or(false) ensures a new boolean flag can never accidentally default to true or skip its gate; the full existing suite passes unchanged, confirming no behavioural drift.

[mikewheeleer]

nice refactor — the typed flag accessors cut a lot of unwrap_or(false) noise. lgtm