feat(frank-dragoon): run the XDNA2 NPU lane beside the flash model

halogen-flash-server already ships an NPU path on the pin we run: for each
model named in HALOGEN_NPU_MODELS it loads the vendor's precompiled AIE
programs (XDNA2 executes only AIE-compiled graphs) and answers them on
/v1/embeddings inside the SAME container behind port 7770. That gives the
fleet an in-house embedding endpoint without touching the iGPU trunk.

The lane is opt-in and one line wide: HALOGEN_NPU_MODELS blank is the
pre-lane endpoint byte for byte (no device, no mounts, no engine env).

The three host preconditions the vendor names are gated in the serve script
and mirrored in the deployer (the 2026-10-01 twin law), each refused by name:
  - the staged model files. /models is read-only and HALOGEN_DOWNLOAD stays
    unset so the container opens no outbound connection at boot, so
    scripts/download-frank-dragoon-npu.sh stages them from the pinned
    revision with the catalog's own byte counts and sha256s (the engine
    re-checks both at boot);
  - the distro XRT's libxrt_coreutil/libxrt_core/libxrt_driver_xdna, each
    mounted twice — where the image looks for XRT and at its own path —
    because those libraries find each other where they were installed and
    an /opt/xilinx/xrt of symlinks dangles inside the container;
  - the GPU fabric clock HELD. On Strix Halo the iGPU and the NPU co-running
    hang the machine (and corrupt NPU results) while FCLK changes speed, and
    halogen refuses to start in that state; it cannot read host sysfs from
    inside, so the hold is proven host-side. dankclaw/host/ carries the
    vendor's halogen-fabric-clock{,.service} verbatim at tag v0.16.2 (sha256
    a3a4f7f4e0142e71… / 5f9f1cc4c85a1c02…); the deployer installs, enables
    and gates it only while the lane is named, and releases the clock plus
    drops the boot hook when it is not.

After health, the deployer's lane gate is a real embedding through
/v1/embeddings — a 200 on /health proves nothing about the NPU programs.

Planner: dankclaw/host/halogen-fabric-clock* re-dispatches frank-dragoon
(the deployer installs it); dankclaw/host/grub and the fetch script plan
nothing.

Seam: 11 new tests — the off arm really renders nothing lane-specific, the
on arm renders the device/mounts/env, every missing precondition refuses by
name, the deployer twins and the host unit shape are pinned.

Co-Authored-By: omp <omp@dankclaw>

scripts/deploy-plan.py

@@ -293,6 +293,17 @@ def services_for_path(path: str, target: str) -> set[str]:
         if len(parts) >= 2 and parts[1] in {"caddy", "comfyui", "loki", "alloy", "hermes", "anubis", "seerr"}:
             _add(services, parts[1])
             return services
+        if len(parts) >= 3 and parts[1] == "host":
+            # Host state a service needs at boot lives under dankclaw/host/.
+            # The fabric-clock hold is frank-dragoon's NPU precondition (the
+            # engine refuses to start with HALOGEN_NPU_MODELS set while the
+            # clock moves) and the deployer installs and gates it, so changing
+            # it re-dispatches that endpoint. `grub` is the tracked boot line,
+            # which moves only through scripts/set-dankclaw-bootline.sh and is
+            # a reboot decision — it plans no service.
+            if parts[2].startswith("halogen-fabric-clock"):
+                _add(services, "frank-dragoon")
+            return services
         if len(parts) >= 4 and parts[1] == "authentik" and parts[2] == "quadlet":
             name = parts[3].removesuffix(".container")
             if name in {"authentik-postgres", "authentik-server", "authentik-worker", "authentik-outpost", "authentik-outpost-ldap"}: