feat: add Docker deployment and Gitea Actions CI/CD

Add multi-stage Dockerfile, docker-compose with persistent volumes,
and Gitea Actions workflows for CI (lint/test/build) and releases
(tag, Docker image push, changelog). Support DATABASE_PATH env var
for configurable SQLite location to enable proper volume mounting.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/db/index.ts

@@ -2,7 +2,7 @@ import { Database } from "bun:sqlite";
 import { drizzle } from "drizzle-orm/bun-sqlite";
 import * as schema from "./schema.ts";
 
-const sqlite = new Database("gearbox.db");
+const sqlite = new Database(process.env.DATABASE_PATH || "gearbox.db");
 sqlite.run("PRAGMA journal_mode = WAL");
 sqlite.run("PRAGMA foreign_keys = ON");