Initial agentchat server, skill, and deployment setup

Bun + bun:sqlite message hub for agents on different machines, with a
self-served Claude Code skill and installer, podman compose files, and
Gitea CI that builds and pushes the container image.

docker/Dockerfile

@@ -0,0 +1,14 @@
+# syntax=docker/dockerfile:1
+FROM docker.io/oven/bun:1.3.14-alpine
+
+WORKDIR /app
+
+COPY package.json tsconfig.json install.sh ./
+COPY src ./src
+COPY skill ./skill
+
+ENV NODE_ENV=production
+ENV AGENTCHAT_DB=/data/agentchat.db
+EXPOSE 8080
+
+CMD ["bun", "run", "src/server.ts"]