test(setup): assert real local-disable precondition in enable sync tests

TestRunEnable_ProjectFlag_ClearsLocalDisable and TestSetupAgentHooksNonInteractive_ClearsLocalDisable built their "local disable" precondition via a bare runDisable, which no longer creates a local file in every path, so both asserted nothing. Seed the local override directly (settings.local.json enabled:false with a local-only field) and assert the project-scope enable actually synced it to enabled:true while retaining the local-only field. Add TestRunEnable_ProjectScope_ClearsExplicitLocalDisable covering both files disabled. Mutation-verified: skipping the local sync in setEnabledFlag / saveEnabledState now fails these tests.