os_install_actuator_selection: match on the optional .first() (latent T? == T exposed by #13179)

[gunbai-bot]

#13179 (EqualityOptionalityMismatch) made the checker refuse T? == T. Five sites on main were never migrated and are latent: any floor subject that reaches gunbc.os_install_actuator_selection refuses them (they surfaced on #13217's floor).

• gunbc.os_install_actuator_selection, the srv3_os_install_actuator_host_selected_because_requirements_and_policy tie-break arm: order.first() == operator_host_srv1
• test.claim.os_install_actuator_selection: os_install_actuator_requirements_dispatch_through_kind_rows (2 sites) and srv3_actuator_host_selected_because_requirements_and_policy (2 sites)

The fix matches on the optional. It does not use == Present { value: .. }, even though the diagnostic offers that remedy first. Executed, opt == Present { value: X } evaluates false when opt is Present { value: X }. The same claim written as match opt { Present { value: X } => true _ => false } passes. Per-conjunct probes at the Present variant (claim_batch, seed evaluator): zz_a1 (kinds.first() == Present { value: BmcNetworkReach }) FAIL; zz_c1 (match on the same optional) PASS. The production predicate srv3_os_install_actuator_host_selected_because_requirements_and_policy also went false under it. So the Present remedy would have compiled clean and silently flipped a production decision. That evaluator defect is reported for separate routing; this PR does not touch it.

Receipt: executed claims at e35849b

Remote run: claim_batch at a 22 GiB cgroup bind, peak 12.9 GiB.

PASS os_install_actuator_requirements_dispatch_through_kind_rows
PASS satisfiable_selection_still_yields_the_selected_actuator_target
PASS srv3_actuator_host_failover_fixture_selects_srv2
PASS srv3_actuator_host_selected_because_requirements_and_policy
PASS srv3_actuator_selection_live_fleet_never_unsatisfiable
PASS unsatisfiable_selection_names_the_selection_not_the_inventory
PASS unsatisfiable_selection_refuses_the_nbd_proxy_serve_step
PASS unsatisfiable_selection_yields_no_actuator_target
rc=0

Mutant: the expected first kind is swapped to ActuatorToolchainGrant, and os_install_actuator_requirements_dispatch_through_kind_rows FAILs. A second mutant meant to swap the srv1/srv2 order did not change the file, because its pattern missed, so it discriminates nothing and I am not counting it.

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