ci: gates/test require git-history, deny requires cargo-deny

[MattJackson]

Declares what three checks need so placement routes them correctly:

• gates: requires git-history (the ceiling ratchet reads the merge-base)
• test: requires git-history (selftests run the gates over the real tree)
• deny: requires cargo-deny

Config only; validated with ModernCI branch_file_check (ok: true).

[github-actions]

promote into predev: all green @2fe3ee3e1

Already red on predev, not this PR's: 13

gate	row	detail
test:xtask-selftest	::xtask selftest kind-isolation
test:xtask-selftest	::xtask selftest no-deferral-strict-done
test:xtask-selftest	::xtask selftest plane-purity-strict
test:xtask-selftest	::xtask selftest unconstructed
test:xtask-selftest	::xtask selftest plane-transport-neutrality
construction	one-pick-site	3 production call site(s) of 'pick_among(' (ceiling 2): crates/busbar-kernel-egress/src/walk.rs:358; crates/busbar-llm/src/engine/exhaustion/fallback.rs:120; crates/busbar-llm/src/engine/pipeline.rs:8
kind-isolation	kind-isolation:deps	3 finding(s), 92 shipped edge instance(s) over 29 class(es), 92 declaration(s); 55 '[[dep]]' row(s), 0 question(s): unlisted-dep-edge legacy -> plane busbar-llm -> busbar-plane-llm is a shipped edge w
kind-isolation-ship	kind-isolation:deps	8 finding(s) over 92 shipped edge(s): ship-edge kernel -> store busbar-kernel -> busbar-store-memory is 'not-allowed': the architecture grants no kernel -> store edge, and the ship criterion is the ar
kind-isolation-ship	kind-isolation:test-deps	5 finding(s) over 31 test edge(s): ship-edge cleanliness -> export busbar-core-admin -> busbar-export-prometheus is 'not-allowed': the architecture grants no cleanliness -> export edge, and the ship c
kind-isolation-ship	kind-isolation:faces	2 finding(s) over 40 crate(s): foreign-entry crates/busbar busbar is kind 'root' and implements 'Transport' 1 time(s) in shipped source — the entry face of kind 'transport'. A trait implementation is
kind-isolation-ship	kind-isolation:legacy-drain	3 finding(s): transitional-live qa/kind-isolation.toml 'busbar-a2a -> busbar-core-admin' (legacy drain: the retiring A2A engine's tests drive the admin surface that drained into the cleanliness tier)
ship-ready	ship-ready:ship-twin	'kind-isolation-ship' is not green: kind-isolation:deps (a dependency the architecture does not grant is still in the graph); kind-isolation:test-deps (a dependency the architecture does not grant is
structure-lint	structure-lint:plane-dup:unledgered	22 finding(s): PLANE-DUPLICATE (module): 'config.rs' — a2a:crates/busbar-a2a/src/a2a/config.rs decisions:crates/busbar-plane-decisions/src/config.rs voice:crates/busbar-voice/src/config.rs (the ledger

tests passed: 24853, failed: 0. Run: https://github.com/GetBusbar/busbar/actions/runs/38372351622 . Artifact verdict-2fe3ee3e10a6cf445b9c9147394402aea5301065 (failures.json, junit.xml, raw.log; 90 days).