Build btop 1.4 from source with AMD GPU support

apt's btop on 24.04 is 1.3.x, which has no AMD GPU monitoring. 1.4+
adds it but requires C++23, which gcc-13 (24.04 default) doesn't fully
support. Plan:

- Add ubuntu-toolchain-r/test PPA, install g++-14 (C++23-capable).
- Add librocm-smi-dev to ROCm host diagnostics — btop dlopens
  librocm_smi64 at runtime; the headers are needed at compile time.
- Drop btop from apt list, build from a pinned BTOP_VERSION tag with
  GPU_SUPPORT=true CXX=g++-14 -j; install to /usr/local/bin.
- Idempotent — only rebuilds if installed version doesn't match.

After deploy: btop → Esc → Options → "show_gpu_info" → On to enable
the GPU panel.

Also clean up TODO.md — the box is on 24.04 (noble), not 26.04. The
libxml2 ABI mismatch / "ROCm gap" section was stale.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

TODO.md

@@ -2,13 +2,11 @@
 
 ## ROCm / vLLM on Strix Halo (gfx1151)
 
-The Framework Desktop runs **Ubuntu 26.04 LTS**; AMD only ships ROCm
-7.2.3 packages for jammy (22.04) and noble (24.04). We installed the
-noble repo but pulled only `rocminfo` + `rocm-smi-lib` for host-side
-diagnostics — all heavy ROCm work runs in containers, which ship their
-own ROCm stack. This sidesteps the host-side libxml2 ABI mismatch (noble
-ships `libxml2.so.2`, 26.04 ships `libxml2.so.16`) that broke the native
-HIP toolchain.
+The Framework Desktop runs **Ubuntu 24.04 LTS (noble)**, which aligns
+with AMD's ROCm 7.x packaging. The deploy installs `rocminfo` and
+`librocm-smi-dev` host-side; heavier ROCm bits (full HIP toolchain,
+device-mapped libraries) still run inside containers that ship their
+own ROCm stack. The host stays slim by design.
 
 ### Open questions
 
@@ -17,21 +15,15 @@ HIP toolchain.
   gfx1151 (RDNA 3.5 consumer) is a different ISA. If the stock image
   doesn't initialize the device, try `rocm/vllm-dev:nightly` or build
   from source against ROCm 7.x with `-DAMDGPU_TARGETS=gfx1151`.
-- **AMD support for 26.04** — watch https://repo.radeon.com/amdgpu-install/<latest>/ubuntu/
-  for a directory matching the box's codename. AMD historically lags
-  Ubuntu LTS by 6–12 months for ROCm packaging.
 
-### When 26.04 ROCm packages land
+### If you ever want full host-side ROCm
 
-If you ever want to do native ROCm work on the host (rather than via
-containers):
-1. Bump `ROCM_VERSION` and `AMDGPU_INSTALL_DEB` in `pyinfra/deploy.py`
-   to the new release.
-2. Update the apt source URL path in `deploy.py` if AMD adds a new
-   release codename (currently hardcoded to `noble`).
-3. Add a step that runs `amdgpu-install -y --usecase=rocm --no-dkms`
-   (the current deploy explicitly avoids this to stay slim).
-4. `./run.sh`.
+For native ROCm work on the host (compiling HIP kernels, full toolchain):
+1. Bump `ROCM_VERSION` and `AMDGPU_INSTALL_DEB` in
+   `pyinfra/framework/deploy.py` to the latest release.
+2. Add a step that runs `amdgpu-install -y --usecase=rocm --no-dkms`
+   (currently avoided to stay slim — ~25 GB toolchain).
+3. `./run.sh`.
 
 For container-only workflows (current default), no action is needed —
 container images update independently of the host.