Add Oh My Pi and improve dev container config

- Install @oh-my-pi/pi-coding-agent and move Go binaries to /usr/local/bin
- Add omp-data volume and make web port configurable via PORT_WEB
- Replace aider self-check with omp in Makefile
- Harden entrypoint: avoid exporting API keys to SSH env and overwrite
  mounted public key into authorized_keys
- Add .dockerignore, simplify .env.example, and document omp in README

vibe-dev/.dockerignore

@@ -0,0 +1,30 @@
+# 版本控制
+.git
+.gitignore
+
+# 敏感文件 (防止意外打入镜像)
+.env
+.env.*
+!.env.example
+*.pem
+id_rsa*
+authorized_keys
+
+# 构建产物
+/target/
+node_modules/
+/dist/
+/build/
+
+# 编辑器与系统
+.vscode/
+.idea/
+*.swp
+*.swo
+.DS_Store
+Thumbnails.db
+
+# 日志与临时
+*.log
+tmp/
+temp/