Add versioned Docker builder tags and Settings about block

Tag Docker builder images with the current application version in both Linux Docker build scripts so different release environments do not overwrite each other with one floating builder tag.

Replace the Settings Scheduler note with an About block that shows the GoSentry version, Go runtime version, Fyne module version, and the project repository link.

scripts/build-linux-docker.sh

@@ -6,6 +6,7 @@ set -euo pipefail
 # default includes the application version and target platform.
 version="$(sed -n 's/^var Version = "\(.*\)"/\1/p' src/core/version.go)"
 version="${version:-0.0.0-dev}"
+tag="gitea.mixdep.ru/mix/pysentry-builder:${version}"
 output="${1:-dist/linux/pysentry-${version}-linux-amd64}"
 docker_user_args=()
 if command -v id >/dev/null 2>&1; then
@@ -14,7 +15,7 @@ fi
 
 # Dockerfile contains the native packages required by Fyne. Keeping that
 # environment in Docker makes Linux builds repeatable from Windows hosts and CI.
-docker build -f Dockerfile -t gitea.mixdep.ru/mix/pysentry-builder .
+docker build -f Dockerfile -t "$tag" .
 
 mkdir -p "$(dirname "$output")"
 docker run --rm \
@@ -24,7 +25,7 @@ docker run --rm \
     -e "GOCACHE=/tmp/go-build-cache" \
     -v "$(pwd):/src" \
     -w /src \
-    gitea.mixdep.ru/mix/pysentry-builder \
+    "$tag" \
     bash -c 'CGO_ENABLED=1 GOOS=linux GOARCH=amd64 go build -buildvcs=false -trimpath -ldflags "-s -w -X github.com/pysentry/pysentry/src/core.Version=${VERSION}" -o "${OUTPUT}" ./cmd/pysentry'
 
 # Icons are embedded in the Go binary, so there is no assets directory to copy