Add Gitea Actions CI and release workflows and deployment assets

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

deploy/docker-compose.yml

@@ -0,0 +1,18 @@
+# Run Hammerhead with Docker:
+#   cp .env.example .env     (then fill it in: at least HAMMERHEAD_MASTER_KEY, see `hammerhead -genkey`)
+#   docker compose up -d
+#
+# Put it behind HTTPS (a reverse proxy, or Blacktip once it's running) and set
+# HAMMERHEAD_URL to the public address in .env.
+services:
+  hammerhead:
+    image: git.veillax.com/veillax/hammerhead:latest
+    restart: unless-stopped
+    env_file: .env
+    ports:
+      - "8080:8080"
+    volumes:
+      - hammerhead-data:/data
+
+volumes:
+  hammerhead-data: