# Infrastructure Layer
## Overview
Implementations of external interfaces (Database, Git, System).
## Entry Points
- `db.rs` owns SQLite persistence and query execution.
- `git.rs` and `git/` own git operations behind `GitClient`.
- `channel.rs` and `agent.rs` own provider transport and prompt execution.
- `app_server.rs` and `app_server/` own shared app-server runtime infrastructure.
- `file_index.rs` owns gitignore-aware file traversal used by `@` mentions and explorer
features.
## Change Guidance
- Keep new external integrations behind trait boundaries.
- Route subprocess, filesystem, and time access through existing infrastructure
boundaries instead of introducing direct calls in orchestration layers.