Initial commit: Triple-C app, container, and CI

Tauri v2 desktop app (React/TypeScript + Rust) for managing
containerized Claude Code environments. Includes Gitea Actions
workflow for building and pushing the sandbox container image,
and a BUILDING.md guide for manual app builds on Linux and Windows.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/src-tauri/src/docker/mod.rs

@@ -0,0 +1,9 @@
+pub mod client;
+pub mod container;
+pub mod image;
+pub mod exec;
+
+pub use client::*;
+pub use container::*;
+pub use image::*;
+pub use exec::*;