Unblocks the ubuntu 26.04 builds without waiting for an image rebuild.
## What broke
```
i Installing R package dependencies
! Error in installing dependencies for package huge with tag 2.0.1:
uvr sync --install-system-deps --library /mnt/cache/R-pkgs-4.4 failed (exit 1)
! WARN Missing system dependencies for 1 package(s)
igraph needs: libglpk-dev
> Running: apt-get install -y libglpk-dev
E: Unable to locate package libglpk-dev
```
Neither the package name nor the sysreq mapping is wrong. `libglpk-dev` is `5.0-2build1` in `universe`, which `ubuntu:resolute` enables by default. What is missing is the apt index: uvr v0.4.5 runs `apt-get install` with no `apt-get update` before it, and every ubuntu build image ends its apt layers with `rm -rf /var/lib/apt/lists/*`, so the shipped image has no index at all.
Not specific to 26.04 — jammy and noble fail identically for any sysreq the image's preinstall line doesn't already cover. 26.04 surfaced it first, through `igraph` and everything depending on it (`huge` was the first to fail).
## Fix
`apt-get update` before the sync in `local/uvr-install.sh`.
That one site covers every pipeline: `build-all-versions`, `build-all-versions-install-deps`, `weekly-rebuild-missing`, `weekly-audit-missing`, `trial-build-registry`, `auto-apply-patches` and `weekly-patch-proposals` all reach it, either directly or through `install-bincraft.R`. The index it populates persists for the rest of the step, so the bincraft-driven `uvr sync` calls that follow are covered too.
Guarded on `apt-get` and non-fatal: `apk add` fetches its index implicitly and dnf refreshes expired metadata on its own, so alpine and redhat are unaffected and skip it.
## Why here as well as in the image
The real fix is upstream `e491b2e`, which refreshes the index before the auto-install. It landed one day after v0.4.5 was tagged, so no release carries it ([nbafrank/uvr#250](https://github.com/nbafrank/uvr/issues/250)); [build-env-images#23](https://codefloe.com/rpkgs/build-env-images/pulls/23) pins the ubuntu image to a commit that has it.
That only reaches CI after an image rebuild is triggered. This change takes effect on the next pipeline run. It also stays useful afterwards: a baked index goes stale within weeks, and a stale index turns the same install into a 404 on the `.deb`.
## Verified
In `ubuntu:resolute`, with the image state reproduced exactly (R installed, then `rm -rf /var/lib/apt/lists/*` to empty the index again):
| Check | Result |
|---|---|
| `apt-get install -y libglpk-dev`, empty index | `E: Unable to locate package libglpk-dev` — the reported failure, reproduced |
| Same container after `apt-get update` | `Candidate: 5.0-2build1`, `Components: main universe restricted multiverse` |
| `igraph` + `UVR_INSTALL_SYSREQS=1 uvr sync`, empty index, uvr with the refresh | `Setting up libglpk-dev:amd64 (5.0-2build1)`, `System dependencies installed.`, `Installed 11 package(s)` |
| `sh -n` and `shellcheck local/uvr-install.sh` | pass |
## Reverting
Delete the guarded block. It is marked TEMPORARY with the upstream reference, and can go once the images ship a uvr above v0.4.5.
Reviewed-on: #161
pat-s
6372f0f928