Implement Pravda: Truth Social to Discord relay service

- Add core modules: database (SQLite), media (ffmpeg), discord (webhook), poller (truthbrush), server (FastAPI)
- Support video transcoding to H.264/AAC with automatic size management
- Handle message splitting for Discord limits (2000 chars, 10 attachments)
- Include interactive buttons (Delete, View Raw, Original Post)
- Add Dockerfile with ffmpeg and entrypoint script
- Add Gitea Actions workflow for CI/CD
- Configure code style tools (black, ruff, mypy)
- Include basic unit tests

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

entrypoint.sh

@@ -0,0 +1,15 @@
+#!/bin/bash
+set -e
+
+# Pravda entrypoint script
+# Detects whether to run in daemon mode or one-off mode based on arguments
+
+if [ $# -gt 0 ]; then
+    # One-off mode: relay a specific post URL
+    echo "Running in one-off mode..."
+    exec python main.py "$@"
+else
+    # Daemon mode: run poller + server
+    echo "Running in daemon mode..."
+    exec python main.py
+fi