refact(deployer): one MainPID gate for all three LLM endpoints

frank-dragoon's health gate never checked WHO answered :7770 — the
false-green the fleet learned about on 2026-09-26 (a stray probe holding
the port satisfies a bare curl while the unit is stopped). The other two
handlers carried that check as inlined copies; all three now call
assert_unit_owns_port, and dragoon gets the protection it was missing.

The seam follows: the endpoints' text-grep deployer tests are deleted,
because tests/llm_deploy_gates.bats EXECUTES the same handlers end to end
(stub systemctl/podman/sudo/ss/curl) and asserts refusals, restarts, unit
links, the pending marker, and the MainPID hardening. GATE_PREFIX is
exported at each handler for the same reason the serve scripts export it.

tests/frank_archon_unit.bats

@@ -419,36 +419,3 @@ serve_run() {
     ! grep -qE '^(TEMP|HOST|GPU_MAX_HEAP_SIZE)=' "$ENV_FILE"
     ! grep -qE '^(export )?(TEMP|HOST|GPU_MAX_HEAP_SIZE)=' "$SERVE"
 }
-
-@test "the deployer gates the image, payload and containers, then health-checks" {
-    # The deployer refuses when the image is absent from dank's rootless
-    # storage or the .rad is missing/too small — then clears stale
-    # containers (including the legacy identities), waits out the port,
-    # relinks/enables/restarts the root unit and health-gates it.
-    grep -q 'LLM_ARCHON_CONTAINER=frank-archon$' "$REMOTE_DEPLOY"
-    grep -q 'FRANK_ARCHON_IMAGE' "$REMOTE_DEPLOY"
-    grep -q 'podman image exists' "$REMOTE_DEPLOY"
-    grep -q 'FRANK_ARCHON_MODEL_FILE' "$REMOTE_DEPLOY"
-    grep -q 'FRANK_ARCHON_RAD_MIN_MIB' "$REMOTE_DEPLOY"
-    grep -q 'frank-archon-qwen' "$REMOTE_DEPLOY"
-    grep -q 'qwen-fp8' "$REMOTE_DEPLOY"
-    grep -q 'glm-probe' "$REMOTE_DEPLOY"
-    grep -q 'wait_port_free 7770' "$REMOTE_DEPLOY"
-    grep -q 'relink_unit frank-archon' "$REMOTE_DEPLOY"
-    grep -q 'systemctl enable frank-archon.service' "$REMOTE_DEPLOY"
-    grep -q 'systemctl restart frank-archon.service' "$REMOTE_DEPLOY"
-    # The health gate is a bare curl: the HTTP listener binds AFTER the
-    # full load (main.cpp — engine.start() then engine.serve()), so during
-    # load the port refuses connections and a bare curl is honest. The
-    # FreeToken-era body read ('status ok') is gone with that engine.
-    grep -q 'curl -fsS http://127.0.0.1:7770/health' "$REMOTE_DEPLOY"
-    ! grep -q '"status":"ok"' "$REMOTE_DEPLOY"
-}
-
-@test "the deployer will not report green on a stray port-holder" {
-    # The 2026-09-26 false green: a leftover probe held :7770 and satisfied
-    # the health curl while the real unit was stopped. The deploy is only
-    # green when the unit's own MainPID is live behind the health answer.
-    grep -q 'systemctl show -p MainPID --value frank-archon.service' "$REMOTE_DEPLOY"
-    grep -q 'stray process holds the port' "$REMOTE_DEPLOY"
-}