feat: add an updates card showing nvtable's package table

Moves the nvchecker/nvtable table the login shell printed onto the
dashboard, as a wide card at the bottom centre. bin/updates-sample.sh
caches `nvtable -C -E` every ten minutes and starts nvchecker, fully
detached, at most every 30 minutes. The widget parses the cache and
colours it in the board's language: installed behind upstream is
critical, a shipped .info behind is a warning, with nvtable's status
dots per row and a legend on the bottom line. The mouse wheel scrolls
rows that do not fit.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

1 files changed, 21 insertions, 2 deletions

diff --git a/README.md b/README.md
index a78371e..59e5797 100644
--- a/README.md
+++ b/README.md
@@ -63,7 +63,7 @@ in the source, so no real location appears in committed files.
 
 ## System widgets
 
-Six cards cover the machine itself:
+Seven cards cover the machine itself:
 
 - **System**: CPU load as a per-core equaliser, the CPU and motherboard model
   as two rows under the header, RAM used/total, and every temperature (CPU
@@ -78,12 +78,14 @@ Six cards cover the machine itself:
   lines on one chart. See below.
 - **Slackware**: distribution version, package count, kernel, install age, and
   time since the last `slackpkg` ChangeLog update. See below.
+- **Updates**: nvtable's table of tracked packages behind upstream, scrolled
+  with the mouse wheel. See below.
 
 The disks and cache cards read a cache file that a sampler writes; they never
 call `du` or `statfs` themselves. `statfs` on an unreachable NFS path blocks,
 and the disks sampler exists so that a dead server costs a stale cache rather
 than a frozen draw. Sampling is scheduled by conky itself: `conky.text` carries
-six `${execi}` entries, even though that block renders nothing under Cairo.
+an `${execi}` per sampler, even though that block renders nothing under Cairo.
 
     ${execi 900  ~/.config/conky/bin/weather-fetch.sh}
     ${execi 60   ~/.config/conky/bin/disks-sample.sh}
@@ -92,6 +94,7 @@ six `${execi}` entries, even though that block renders nothing under Cairo.
     ${execi 900  ~/.config/conky/bin/slackware-sample.sh}
     ${execi 300  ~/.config/conky/bin/calendar-sample.sh}
     ${execi 1800 ~/.config/conky/bin/immich-fetch.sh}
+    ${execi 600  ~/.config/conky/bin/updates-sample.sh}
 
 The disks sampler runs once a minute; the cache, Slackware and public-IP
 samplers run every 15, 15 and 30 minutes respectively, because `du -sh
@@ -110,6 +113,7 @@ To run a sampler by hand:
     ./bin/pubip-sample.sh; echo "exit: $?"
     ./bin/slackware-sample.sh; echo "exit: $?"
     ./bin/calendar-sample.sh; echo "exit: $?"
+    ./bin/updates-sample.sh; echo "exit: $?"
 
 All print nothing and exit 0 on success, and all write a temp file and rename
 it over the target, so the widget never reads a half-written file.
@@ -216,6 +220,21 @@ The key sits in a plain file, like the weather key, because the fetch runs
 unattended from conky: reading it from a GPG-backed store would raise a
 pinentry whenever the agent's cache has expired.
 
+### Updates
+
+nvtable's table of tracked packages that need action: where each is
+installed, the version its SlackBuild ships and, when that is not it, the
+upstream release. The big value is how many installed packages are behind
+upstream. Installed versions read red when behind and green when caught up,
+a shipped `.info` behind upstream reads as a warning. Rows that do not fit
+scroll with the mouse wheel, with a thin scrollbar at the right edge.
+
+`bin/updates-sample.sh` runs every ten minutes and caches `nvtable -C -E`
+in `~/.cache/udt/updates.txt`. It also starts `nvchecker` in the background
+at most every 30 minutes, detached so conky never waits on the network; its
+results show up on the next sample. `nvtable` is looked up in `~/bin` too,
+since conky launched by the compositor lacks the login shell's `PATH`.
+
 ### Host bindings
 
 These hwmon bindings, and the ceilings beside them, are specific to this machine