Set the chart's placeholder version to 0.16.1

Cosmetic, and done anyway. release.yaml passes --version and --app-version
from the git tag when it packages, so neither line decides anything about
what is published; they exist to be read by somebody looking at the tree
before the tag does. A tree heading for v0.16.1 that says 0.16.0 tells that
reader something false.

Its own commit, like 828cf87, 8869ac8 and 9376105 before it, so the feature
commit's diff stays the feature.

Claude-Session: https://claude.ai/code/session_01RHPj4ggeFdEjKKfm4SHbD7

charts/terdut-server/Chart.yaml

@@ -15,5 +15,5 @@ type: application
 # appVersion and image.tag in values.yaml no longer agree, and that is not an oversight:
 # image.tag stays "latest", which is what a local install actually pulls. appVersion is
 # metadata and drives nothing.
-version: 0.16.0
-appVersion: "v0.16.0"
+version: 0.16.1
+appVersion: "v0.16.1"