Add sync_and_release.sh for one-command upstream sync and deploy

Fetches upstream, fast-forwards master, merges to build,
creates tag, and pushes everything with confirmation prompt.

Author: klhq

sync_and_release.sh

@@ -0,0 +1,54 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+# Ensure clean working tree
+if [ -n "$(git status --porcelain)" ]; then
+    echo "Error: Working tree is not clean. Commit or stash changes first."
+    exit 1
+fi
+
+# Ensure merge=ours driver is configured (needed for README.md)
+git config merge.ours.driver true
+
+# 1. Fetch upstream
+echo "==> Fetching upstream..."
+git fetch upstream
+
+# 2. Fast-forward master to upstream/master
+echo "==> Updating master..."
+git checkout master
+git merge --ff-only upstream/master
+
+# 3. Merge master into build (README auto-resolved via merge=ours)
+echo "==> Merging master into build..."
+git checkout build
+git merge master
+
+# 4. Create tag from version in CMakeLists.txt
+echo "==> Creating tag..."
+./add_git_tag.sh
+
+# Extract version for push
+VERSION=$(awk '/project\(TDLib VERSION/ {print $3}' CMakeLists.txt | tr -d '[:space:]()')
+
+# 5. Summary
+echo ""
+echo "========================================="
+echo "  Ready to push"
+echo "========================================="
+echo "  master  → origin/master"
+echo "  build   → origin/build"
+echo "  tag     → ${VERSION}"
+echo "========================================="
+echo ""
+read -p "Push all? [y/N] " -n 1 -r
+echo ""
+
+if [[ $REPLY =~ ^[Yy]$ ]]; then
+    git push origin master build "${VERSION}"
+    echo ""
+    echo "Done! CI/CD will build and release ${VERSION}."
+else
+    echo "Aborted. You can push manually:"
+    echo "  git push origin master build ${VERSION}"
+fi