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.

scripts/deploy-remote.sh

@@ -1166,6 +1166,20 @@ wait_port_free() {
     ss -tan "sport = :$port" >&2 || true
     return 1
 }
+# assert_unit_owns_port SERVICE PORT — the false-green gate every LLM
+# endpoint shares. A health answer proves the PORT replied, never WHO
+# replied: on 2026-09-26 a leftover probe held :7770, satisfied the curl,
+# and the deploy reported green over a stopped unit. Green requires the
+# unit's own MainPID to be alive behind the answer.
+assert_unit_owns_port() {
+    local service="$1" port="$2" main_pid
+    main_pid="$(run_privileged systemctl show -p MainPID --value "$service.service")"
+    if [[ -z "$main_pid" || "$main_pid" == "0" ]]; then
+        echo "FAIL: :$port answered but $service.service has no MainPID — a stray process holds the port" >&2
+        return 1
+    fi
+    echo "$service: health answered by unit MainPID $main_pid"
+}
 
 deploy_llm_dragoon() {
     # Refuse rather than restart-loop; every gate here is the SAME library
@@ -1173,7 +1187,7 @@ deploy_llm_dragoon() {
     # 2026-10-01 crash-loop lesson).
     # Capture podman output before grepping is moot: require_image is one
     # command, no pipe (the 2026-09-30 SIGPIPE lesson).
-    GATE_PREFIX=frank-dragoon
+    export GATE_PREFIX=frank-dragoon
     require_image "$LLM_DRAGOON_IMAGE" \
         "pull it: podman pull docker://${LLM_DRAGOON_IMAGE%@*}" || return 1
     require_bytes "$LLM_DRAGOON_CKPT" checkpoint "$LLM_DRAGOON_CKPT_BYTES" \
@@ -1205,7 +1219,8 @@ deploy_llm_dragoon() {
     run_privileged systemctl daemon-reload
     run_privileged systemctl enable frank-dragoon.service
     run_privileged systemctl restart frank-dragoon.service
-    wait_for_health frank-dragoon http://127.0.0.1:7770/health 1200
+    wait_for_health frank-dragoon http://127.0.0.1:7770/health 1200 || return 1
+    assert_unit_owns_port frank-dragoon 7770
 }
 
 # deploy_llm_zealot — frank-zealot is llama.cpp (master build, CUDA sm_86) on
@@ -1231,7 +1246,7 @@ deploy_llm_zealot() {
     # missing never becomes healthy, and a green deploy would leave the
     # endpoint dark with nothing in the log to say why. Same library calls
     # as serve-frank-zealot.sh (the 2026-10-01 law).
-    GATE_PREFIX=frank-zealot
+    export GATE_PREFIX=frank-zealot
     require_exec "$LLM_ZEALOT_RUNTIME" runtime \
         "build it: cmake -B build-cuda -DGGML_CUDA=ON -DCMAKE_CUDA_ARCHITECTURES=86" \
         || return 1
@@ -1245,16 +1260,7 @@ deploy_llm_zealot() {
     run_privileged systemctl enable frank-zealot.service
     run_privileged systemctl restart frank-zealot.service
     wait_for_health frank-zealot http://127.0.0.1:7771/health 900 || return 1
-    # False-green hardening (frank-dragoon's lesson): the port answering
-    # proves nothing about WHO answers — the unit must be active with a
-    # live MainPID, or a stray SGLang holdover is masquerading as deployed.
-    local main_pid
-    main_pid="$(run_privileged systemctl show -p MainPID --value frank-zealot.service)"
-    if [[ -z "$main_pid" || "$main_pid" == "0" ]]; then
-        echo "FAIL: :7771 answered but frank-zealot.service has no MainPID — a stray process holds the port" >&2
-        return 1
-    fi
-    echo "frank-zealot: health answered by unit MainPID $main_pid"
+    assert_unit_owns_port frank-zealot 7771
 }
 
 # deploy_llm_archon — frank-archon is the radiance engine (StillDeadcode,
@@ -1285,7 +1291,7 @@ deploy_llm_archon() {
     # shared library's, called with the values the unit's own env file
     # declares — so serve-frank-archon.sh and this handler cannot disagree,
     # and the payload path lives in exactly one file.
-    GATE_PREFIX=frank-archon
+    export GATE_PREFIX=frank-archon
     local env_file="${LLM_ARCHON_ENV_FILE:-$REMOTE_DIR/scripts/frank-archon.env}"
     local image model_dir model_file rad_min
     if [[ ! -f "$env_file" ]]; then
@@ -1350,17 +1356,7 @@ deploy_llm_archon() {
         echo "FAIL: frank-archon /health never answered 200 in 1800s" >&2
         return 1
     fi
-    # False-green hardening (the 2026-09-26 lesson): a bare curl against the
-    # port cannot tell WHO answers — a stray probe holding :7770 satisfies
-    # it while the unit is stopped. The deploy is only green if the unit
-    # itself is active with a live MainPID behind the health answer.
-    local main_pid
-    main_pid="$(run_privileged systemctl show -p MainPID --value frank-archon.service)"
-    if [[ -z "$main_pid" || "$main_pid" == "0" ]]; then
-        echo "FAIL: :7770 answered but frank-archon.service has no MainPID — a stray process holds the port" >&2
-        return 1
-    fi
-    echo "frank-archon: health answered by unit MainPID $main_pid"
+    assert_unit_owns_port frank-archon 7770
 }
 
 wait_for_health() {

scripts/lib/llm-gates.sh

@@ -32,7 +32,10 @@
 # writes the error body as the artifact), and the declared byte count is a
 # contract in both directions — a bigger file is a DIFFERENT artifact.
 
-# GATE_PREFIX names the endpoint in every refusal (e.g. frank-dragoon).
+# GATE_PREFIX names the endpoint in every refusal (e.g. frank-dragoon). The
+# caller exports it; shellcheck cannot follow it across the source boundary,
+# so the read site carries the directive.
+# shellcheck disable=SC2034
 : "${GATE_PREFIX:=gate}"
 
 # Two bash laws make the `return 1` at every call site load-bearing: