ci: add version consistency check and fully automate release pipeline

- New tools/check_versions.sh: verifies version.txt, version.h, SylDaVersions.kt match
- release.yml: 'Verify version consistency' step after build, aborts release if mismatch
- ci.yml: same check after debug APK build
- scripts/release.sh: now runs full pipeline (pio run -> copy firmware -> gradle -> check)
  and refuses dirty working tree
- Untrack version.h, SylDaVersions.kt, release/ — always regenerated fresh from version.txt

Prevents the v1.1 bug where stale generated files caused version mismatch
and infinite re-flash loop.

tools/check_versions.sh

@@ -0,0 +1,75 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+RED='\033[0;31m'
+GREEN='\033[0;32m'
+NC='\033[0m'
+
+pass() { echo -e "  ${GREEN}OK${NC} $1"; }
+fail() { echo -e "  ${RED}MISMATCH${NC} $1"; }
+
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
+PROJECT_DIR="$(dirname "$SCRIPT_DIR")"
+
+VERSION_FILE="$PROJECT_DIR/version.txt"
+HEADER_FILE="$PROJECT_DIR/src/version.h"
+KOTLIN_FILE="$PROJECT_DIR/android/app/src/main/java/nl/eddydevink/sylda/SylDaVersions.kt"
+
+errors=0
+
+echo "=== Version consistency check ==="
+
+# 1. Parse version.txt (source of truth)
+if [ ! -f "$VERSION_FILE" ]; then
+    fail "version.txt not found at $VERSION_FILE"
+    exit 1
+fi
+
+src_server=$(grep -oP '^server=\K\d+' "$VERSION_FILE" || true)
+src_client=$(grep -oP '^client=\K\d+' "$VERSION_FILE" || true)
+
+if [ -z "$src_server" ] || [ -z "$src_client" ]; then
+    fail "version.txt missing server= or client="
+    exit 1
+fi
+pass "version.txt           server=$src_server client=$src_client"
+
+# 2. Parse src/version.h (generated by pio run)
+if [ ! -f "$HEADER_FILE" ]; then
+    fail "src/version.h not found — run 'pio run' first"
+    ((errors++))
+else
+    hdr_server=$(grep -oP 'FIRMWARE_VERSION_SERVER\s+"\K\d+' "$HEADER_FILE" || true)
+    hdr_client=$(grep -oP 'FIRMWARE_VERSION_CLIENT\s+"\K\d+' "$HEADER_FILE" || true)
+    if [ "$hdr_server" = "$src_server" ] && [ "$hdr_client" = "$src_client" ]; then
+        pass "src/version.h         server=$hdr_server client=$hdr_client"
+    else
+        fail "src/version.h         server=${hdr_server:-MISSING} client=${hdr_client:-MISSING} (expected server=$src_server client=$src_client)"
+        ((errors++))
+    fi
+fi
+
+# 3. Parse SylDaVersions.kt (generated by Gradle build)
+if [ ! -f "$KOTLIN_FILE" ]; then
+    fail "SylDaVersions.kt not found — run './gradlew build' first"
+    ((errors++))
+else
+    kt_server=$(grep -oP 'const val SERVER = "\K\d+' "$KOTLIN_FILE" || true)
+    kt_client=$(grep -oP 'const val CLIENT = "\K\d+' "$KOTLIN_FILE" || true)
+    if [ "$kt_server" = "$src_server" ] && [ "$kt_client" = "$src_client" ]; then
+        pass "SylDaVersions.kt      server=$kt_server client=$kt_client"
+    else
+        fail "SylDaVersions.kt      server=${kt_server:-MISSING} client=${kt_client:-MISSING} (expected server=$src_server client=$src_client)"
+        ((errors++))
+    fi
+fi
+
+echo ""
+if [ "$errors" -eq 0 ]; then
+    echo -e "${GREEN}All version files in sync.${NC}"
+    exit 0
+else
+    echo -e "${RED}$errors version file(s) out of sync with version.txt.${NC}"
+    echo "Run 'pio run' and './gradlew build' to regenerate."
+    exit 1
+fi