docs: personalized dev environment (dotfiles + persistent home)

docs/dotfiles.md

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+# Personalized dev environment (dotfiles + persistent home)
+
+Makes the workspace terminal feel like the user's own machine: a Fedora image
+preloaded with QoL CLI tooling, a persistent per-user home, and user dotfiles.
+
+## The model
+
+- **Persistent per-user home.** Each user gets a home directory on the worker
+  host at `${SPOON_AGENT_WORKDIR}/homes/{username}`, bind-mounted into every
+  job/terminal container at `/home/{username}` (`HOME`). It survives across
+  sessions, so dotfiles, installed tools, nvim plugins, and shell history persist.
+  `username` is derived from the user's profile first name (sanitized).
+- **Threads as folders.** Each thread's checkout lives at
+  `~/Code/{spoon}/{branch}` inside that home, so every thread shows up as a
+  folder in one home. The agent (`codex --cd …`) and the terminal both open there.
+- **Neutral defaults (everyone).** The Fedora job image
+  (`docker/agent-job.Dockerfile`) ships zoxide, eza, bat, fzf, fd, ripgrep, gh,
+  gum, neovim, tmux, oh-my-posh, etc., plus system-wide defaults that work even
+  with an empty home: `/etc/profile.d/spoon.sh` (tool init + aliases),
+  `/etc/tmux.conf` (login-shell panes), `/etc/spoon/omp.json` (prompt theme).
+- **User dotfiles (per-user).** Configured in **Settings → Dotfiles**, applied on
+  top of the neutral defaults.
+
+## Settings → Dotfiles
+
+A mini file-browser workspace rooted at `home/{firstName}`:
+
+- **Editable overlay tree** — drag in files/folders (or use Upload folder/files),
+  edit them in the Monaco editor, add/delete. Files are placed **relative to
+  `$HOME`** (`.bashrc` → `~/.bashrc`, `.config/nvim/…` → `~/.config/nvim/…`).
+  Stored encrypted at rest (`userDotfiles`, AES-256-GCM via `secretCrypto`).
+- **Dotfiles repo (optional)** — a **public** git repo URL + optional ref + a
+  setup script path. On start the container clones it to `~/.dotfiles` and runs
+  `bash ~/.dotfiles/<setup>` (e.g. a bootstrap that symlinks configs, like the
+  user's Panama `install`).
+- **Precedence (hybrid):** repo clone + setup runs first; then the editable
+  overlay is written on top — **overlay wins**.
+
+Secrets: dotfiles are encrypted, but real API keys/tokens belong in a Spoon's
+**Secrets** feature (injected as env vars), not in dotfiles. The UI nudges this.
+
+## Materialization (worker)
+
+`apps/agent-worker/src/user-environment.ts`:
+
+1. `fetchUserEnvironment(jobId)` — a worker-token Convex action
+   (`userDotfilesNode.getEnvironmentForJob`) returns the owner's decrypted
+   dotfiles + repo/setup config.
+2. `materializeUserHome` — ensures `~/.bash_profile` (so login shells source
+   `~/.bashrc` in a mounted home with no `/etc/skel`); clones the repo + runs the
+   setup command **inside the job image** (so the user's tools/paths apply), only
+   when the config hash changes (`~/.spoon/env-hash`); writes the overlay files.
+
+## Configuration
+
+| Variable                                   | Default                                                        | Notes                                                                                    |
+| ------------------------------------------ | -------------------------------------------------------------- | ---------------------------------------------------------------------------------------- |
+| `SPOON_AGENT_WORKDIR`                      | `.local/agent-work` (dev) / `/var/lib/spoon-agent/work` (prod) | Per-user homes live under `homes/{username}`; reuses the existing host-path translation. |
+| `SPOON_ENCRYPTION_KEY` / `INSTANCE_SECRET` | —                                                              | Already required; encrypts dotfiles like other secrets.                                  |
+
+No new required env. The home is a host directory under the existing workdir, so
+the prod bind-mount + `SPOON_AGENT_HOST_WORKDIR` translation already covers it.
+
+## Notes / limits (Phase 1)
+
+- **Repo auth:** public repos only. Private/self-hosted (e.g. Gitea) dotfiles
+  repos are a follow-up (store a token/deploy key).
+- **Binary files:** the overlay is text-first.
+- **Cleanup:** `~/Code/{spoon}/{branch}` checkouts persist (threads as folders);
+  a per-thread "delete checkout" action is a follow-up.
+- **Concurrency:** jobs share one home; fine at the default
+  `SPOON_AGENT_MAX_CONCURRENT_JOBS=1`.
+
+## Phase 2 north star
+
+A single long-running per-user container that every thread `exec`s into (agent
+via `docker exec`, not `docker run --rm`). The per-user home + `~/Code/{spoon}/
+{branch}` layout built here is its foundation.