feat: initial refactor and feature implementation

This is the first major commit after forking the original project. The
script has been almost completely rewritten to add new features.

- Implement AES-256 encryption with configurable PBKDF2 iterations (default 600k).
- Add Telegram integration for status updates and optional file uploads.
- Rework backup logic to use safe `sqlite3 .backup` method.
- Add GitHub Action to build/publish multi-arch Docker images and create
  GitHub Releases on git tags.

BREAKING CHANGE: The project is not backward-compatible, configuration
and behavior are entirely different from the original version.

Dockerfile

@@ -1,25 +1,33 @@
 ARG ARCH=
-FROM ${ARCH}alpine:latest
+FROM ${ARCH}alpine:3.22
 
-RUN addgroup -S app && adduser -S -G app app
-
-RUN apk add --no-cache \
-    busybox-suid \
-    su-exec \
-    xz \
-    tzdata
-
-ENV CRON_TIME "0 */12 * * *"
-ENV UID 100
-ENV GID 100
-ENV DELETE_AFTER 0
+ENV CRON_TIME="0 */12 * * *"
+ENV UID=100
+ENV GID=100
+ENV DELETE_AFTER=0
+ENV BACKUP_ENCRYPTION_KEY=""
+ENV TG_TOKEN=""
+ENV TG_CHAT_ID=""
+ENV VWDUMP_DEBUG="false"
+ENV DISABLE_WARNINGS="false"
+ENV DISABLE_TELEGRAM_UPLOAD="false"
+ENV PBKDF2_ITERATIONS=600000
 
 COPY entrypoint.sh /usr/local/bin/entrypoint.sh
-COPY script.sh /app/
+COPY script.sh /app/script.sh
 
-RUN mkdir /app/log/ \
-    && chown -R app:app /app/ \
-    && chmod -R 777 /app/ \
-    && chmod +x /usr/local/bin/entrypoint.sh 
+RUN addgroup -S app && adduser -S -G app app \
+    && apk add --no-cache \
+        busybox-suid \
+        su-exec \
+        xz \
+        tzdata \
+        openssl \
+        curl \
+        sqlite \
+    && mkdir -p /app/log/ \
+    && chown -R app:app /app \
+    && chmod +x /usr/local/bin/entrypoint.sh \
+    && chmod +x /app/script.sh
 
-ENTRYPOINT ["entrypoint.sh"]
+ENTRYPOINT ["entrypoint.sh"]