feat: badge versione build in GUI + build.sh con auto-bump

- VERSION (1.0.0) + build.sh: bump patch/minor/major e deploy via docker compose
- Dockerfile: ARG/ENV APP_VERSION + BUILD_TIME (iniettati come build-arg)
- version.build_info(): env in Docker, fallback file VERSION + '(local)' in dev
- GET /api/version; badge #appVersionPill nell'header (tooltip = build time)
- test_version.py: env vs fallback

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

build.sh

@@ -0,0 +1,40 @@
+#!/usr/bin/env bash
+# Build + deploy di presa-mano con auto-bump della versione.
+#
+#   ./build.sh            → patch++  (1.0.1 -> 1.0.2)
+#   ./build.sh minor      → minor++  (1.0.2 -> 1.1.0)
+#   ./build.sh major      → major++  (1.1.0 -> 2.0.0)
+#
+# La nuova versione + l'ora di build vengono iniettate nell'immagine come
+# build-arg e mostrate nel badge in GUI. Il file VERSION viene riscritto ma NON
+# committato automaticamente (lo committi tu con le altre modifiche).
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
+COMPOSE_DIR="$(dirname "$SCRIPT_DIR")"   # docker-compose.yml sta un livello sopra
+VERSION_FILE="$SCRIPT_DIR/VERSION"
+
+[ -f "$VERSION_FILE" ] || echo "1.0.0" > "$VERSION_FILE"
+cur="$(tr -d '[:space:]' < "$VERSION_FILE")"
+IFS='.' read -r major minor patch <<< "$cur"
+major="${major:-1}"; minor="${minor:-0}"; patch="${patch:-0}"
+
+case "${1:-patch}" in
+  major) major=$((major + 1)); minor=0; patch=0 ;;
+  minor) minor=$((minor + 1)); patch=0 ;;
+  patch) patch=$((patch + 1)) ;;
+  *) echo "uso: $0 [major|minor|patch]" >&2; exit 1 ;;
+esac
+
+new="${major}.${minor}.${patch}"
+echo "$new" > "$VERSION_FILE"
+build_time="$(date -u +"%Y-%m-%d %H:%M UTC")"
+
+echo "→ build V${new}  (${build_time})"
+cd "$COMPOSE_DIR"
+docker compose build \
+  --build-arg APP_VERSION="$new" \
+  --build-arg BUILD_TIME="$build_time" \
+  presa-mano
+docker compose up -d presa-mano
+echo "✓ deployed V${new}  (${build_time})"