Rosenblatt Phase-1 closeout: rocket-driver substrate inventory

Phase-1 audit closes with a substantively different picture than the
original scaffold's TBDs:

- Tomeu Vizoso's RK3588 NPU work merged in Linux 6.18 (Nov 2025) under
  codename `rocket` (NOT `rknpu`).  All references updated.
- Boltzmann's `linux-rk3588-marfrit-A1` (7.0.0-rc3-ARCH+) already ships
  `drivers/accel/rocket/rocket.ko` as a built-but-not-loaded module.
- DT bindings + per-core nodes (`npu@fdab/c/d_0000`,
  compatible `rockchip,rk3588-rknn-core`) in mainline since 6.18 but
  ship `status = "disabled"` — board enable is the Phase-2 unblock,
  not a driver port.
- Mesa 25.3 ships Rocket Gallium + Teflon TFLite delegate as the
  authoritative userspace reference for the uAPI shape.
- Op coverage today is conv-centric (MobileNet-class); transformer
  matmul needs the conv-1×1 shoehorn (RKNPU2 BSP precedent) or rocket
  op-set additions.  Surfaced as Phase-2-load-bearing risk.
- IOMMU v1.0 hazard: 32 GB host needs `mem=4G` or local
  `rockchip,rk3568-iommu-v1` discriminator patches before the first
  NPU job, to avoid DMA-window faults.

Files:
- docs/npu-mainline-status.md: full audit table with upstream pointers
  (kernel.org / Mesa docs / dri-devel patch URLs / Tomeu's "we are in
  mainline" blog post).
- docs/phases.md: per-phase log entry for Phase-1 closeout.
- docs/op-coverage.md: matmul-vs-conv-vs-rocket-op-set framing.
- fleet/boltzmann.yaml: audited kernel + npu_driver + dt_npu_nodes
  state.
- kernel/dt-overlays/rk3588-rosenblatt-npu-enable.dtso: overlay to
  flip the three rknn-core nodes to "okay" (+ matching mmu nodes),
  carries the IOMMU-mitigation warning inline.
- kernel/README.md: kernel-agent scope wiring + anticipated local
  carry patches.
- README.md: phase-status table + "rknpu → rocket" rename note.
- TODO.md: Phase-2 unblock concrete steps + standing
  upstream-watch items.

README.md

@@ -103,5 +103,12 @@ We're writing the second half.
 | Phase | State | Date |
 |---|---|---|
 | 0 — bootstrap | done | 2026-05-19 |
-| 1 — substrate audit | open | |
-| 2..10 | pending | |
+| 1 — substrate audit | done | 2026-05-19 |
+| 2 — formulate | open | |
+| 3..10 | pending | |
+
+Phase-1 closeout: `docs/phases.md` + `docs/npu-mainline-status.md`.
+Headline: mainline driver name is **`rocket`** (not `rknpu`); it's
+already shipped in boltzmann's kernel as a built module. Phase-2
+unblock is small (DT enable + IOMMU v1.0 mitigation + modprobe),
+not a driver port.