Separately configurable locations for server config, server data, and client files

[colonelpanic8]

TL;DR: ~/.t3 mixes server configuration, server data, and the desktop client's own files under one root, and T3CODE_HOME moves them all together. I'd like each to have its own location you can set. Below is a classification of the existing files, which is the decision #17971 is waiting on. The first step changes no defaults, so it doesn't need a policy for existing installs. Is this direction wanted?

Problem

• T3CODE_HOME / --home-dir / --base-dir is the only location setting. deriveServerPaths in apps/server/src/config.ts derives every path from it.
• userdata/ holds settings.json, keybindings.json, and themes/ next to statev2.sqlite, secrets/, logs, and attachments. Config can't be versioned, backed up, or mounted separately from data, and the database can't move to another disk without taking config with it.
• The desktop app's own files (client-settings.json, desktop-settings.json, connection-catalog.json) also live in the server's userdata/ (DesktopEnvironment.ts, DesktopConnectionCatalogStore.ts), even for a desktop that only connects to remote environments.

Proposed classification

Root	Contents today
Server config	settings.json, keybindings.json, themes/
Server data	statev2.sqlite, attachments/, secrets/, logs/, browser-artifacts/, worktrees/, environment-id, anonymous-id, server-runtime.json
Server cache	caches/
Client config	client-settings.json, the preferences in desktop-settings.json (update channel, WSL)
Client state	window bounds, connection-catalog.json

Staged so defaults don't change

1. Optional overrides for the server config, data, and cache locations (flags plus T3CODE_* env vars). When unset, each derives from the base directory exactly as today.
2. An optional location for the desktop client's files, defaulting to where they are now.
3. Later, and separately: whether new Linux installs default to XDG locations (Honor XDG Base Directory paths on Linux #17971), and what happens to existing ~/.t3 installs. After step 1 that is purely a question about defaults.

Questions

1. Is this classification acceptable? In particular, worktrees and logs as data, and themes/ as config.
2. Would you accept step 1 as a focused PR, given that it changes no defaults?
3. Should the desktop client's files move out of the server directory (step 2)?

Prior art

• The XDG Base Directory spec separates config, data, state, and cache for the same reasons.
• My earlier Use xdg directories: Separate configuration, data, state, cache, and runtime storage #4437 implemented a full five-root layout and was closed as an unsolicited cross-system change. This is the smaller, decision-first version.

Related

• Honor XDG Base Directory paths on Linux #17971: XDG Base Directory paths on Linux
• [Feature]: Provide proper files to move the configuration between environments #6802: configuration files that can live in a dotfiles repo
• Every setting should be expressible in a config file #19592: every setting should be expressible in a config file
• A rule for which settings the client owns and which the environment owns #19593: which settings the client owns and which the environment owns
• Keep dotfile-managed settings separate from machine-local changes #19594: keeping dotfile-managed settings separate from machine-local changes
• [Feature]: Commit to a true graphical client/headless server architecture with first-class remote environments #6811: client/headless-server architecture

[colonelpanic8]

Proposed implementations are on my fork, not opened here:

• feat(server): optional server config, data, and cache locations colonelpanic8/t3code#4: --server-config-dir, --server-data-dir and --server-cache-dir (and T3CODE_SERVER_CONFIG_DIR, T3CODE_SERVER_DATA_DIR, T3CODE_SERVER_CACHE_DIR). Each one moves only its own category; with none set, paths are unchanged. Install commands ignore them, so a background service never picks up a one-off override.
• feat(desktop): optional directory for the desktop app's own files colonelpanic8/t3code#3: --client-dir / T3CODE_CLIENT_DIR for the desktop app's own files.

Happy to open either here if you want them.