Support a configurable Command Code home directory.

Feature Description

Command Code currently stores user-level data in ~/.commandcode with no way to change the base directory.

Add a COMMANDCODE_HOME environment variable, defaulting to ~/.commandcode, and resolve all user-level paths relative to it.

Example:

COMMANDCODE_HOME="${XDG_CONFIG_HOME}/commandcode" cmd

Use Case

Users following the XDG Base Directory Specification, using encrypted or separate storage, or managing multiple environments need control over where Command Code stores its data.

This also avoids placing application-specific directories directly under $HOME.

Additional Context

Other coding agents already provide this:

• Codex: CODEX_HOME
• Claude Code: CLAUDE_CONFIG_DIR
• pi: PI_CODING_AGENT_DIR

The default ~/.commandcode location should remain unchanged for backwards compatibility. Project-local .commandcode directories should continue working as they do currently.

How important is this to you?

Blocking adoption or production use

Inizia individuando il codice che risolve i percorsi attuali a livello utente per ~/.commandcode e il punto di ingresso cmd. Verifica che COMMANDCODE_HOME sovrascriva il valore predefinito, che tutti i percorsi a livello utente lo utilizzino, che il valore predefinito rimanga invariato e che le directory .commandcode locali al progetto continuino a funzionare.