feat: migrate to Poetry and implement multi-backend DNS management ✨

- Migrated from setuptools to Poetry; added pyproject.toml, poetry.lock,
  poetry.toml and .python-version (Python 3.11.12)
- Built out full directdnsonly Python package with BIND and CoreDNS MySQL
  backends, CherryPy REST API, persist-queue worker, and vyper-based config
- Auth credentials now read from config/env (app.auth_username/password)
  rather than hardcoded; override via DADNS_APP_AUTH_PASSWORD env var
- Added Dockerfile.deepseek: Python 3.11 slim + BIND9 + Poetry install
- Rewrote docker-compose.yml for local dev stack (MySQL + dadns services)
- Added SQL schema, docker/ BIND configs, justfile, tests, and README
- Expanded .gitignore for Poetry/Python project artifacts

schema/coredns_mysql.sql

@@ -0,0 +1,12 @@
+CREATE TABLE IF NOT EXISTS `records` (
+  `id` int(11) NOT NULL AUTO_INCREMENT,
+  `zone` varchar(255) NOT NULL,
+  `name` varchar(255) NOT NULL,
+  `ttl` int(11) DEFAULT NULL,
+  `type` varchar(10) NOT NULL,
+  `data` text NOT NULL,
+  PRIMARY KEY (`id`),
+  KEY `idx_zone` (`zone`),
+  KEY `idx_name` (`name`),
+  KEY `idx_type` (`type`)
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;