POS_CONFIG fields gain an optional 'desc::example' value-format hint shown
in the editor ('e.g. weather,5m joke,10m' under ENABLED). Harden
entertainment-lib's plugin_marker/plugin_keys grep|sed pipelines with
'|| true': under set -o pipefail a grep miss exited 1 and set -e aborted
config_keys mid-scan, so installed layouts (/usr/local/bin mixes libs and
plugins) silently lost all plugin keys in pos config.
Add bin/pos-config + lib/config-ui.sh: reads the '# POS_CONFIG:' headers
across tools into a unified runtime config (~/.config/linux_post_install/
<scope>.env, chmod 600). Secret masking with show/hide, digits:/num:/url:
validation, '-' clears, blank keeps; '*plugins' expands entertainment
plugin vars from entertainment-lib.sh. pos config with no scope opens a
picker (scope list when not a TTY); completion offers scopes from the
registry at runtime.
gen-docs.sh now handles category-less tools (pos-config) instead of
emitting pos-config-config; fix set -e/pipefail abort that truncated the
header registry mid-read. install.sh ships config-ui.sh.