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/commands/mod.rs

@@ -0,0 +1,4 @@
+pub mod docker_commands;
+pub mod project_commands;
+pub mod settings_commands;
+pub mod terminal_commands;