Worker Isolation

.enki/
├── copies/
│   ├── task-a1b2c3de/    # Worker copy for task-a1b2c3de
│   │   ├── src/
│   │   ├── build/        # Build artifacts included!
│   │   ├── node_modules/ # Dependencies included!
│   │   ├── .git/         # Full git history
│   │   └── ...
│   └── task-f4e5d6c7/    # Another worker's copy
└── db.sqlite

# You have uncommitted changes:
echo "WIP feature" > feature.rs
# (not committed)

# Worker copy sees feature.rs with "WIP feature"

impl CopyManager {
    /// Create a copy for a worker. Returns (copy_path, base_commit, base_branch).
    pub fn create_copy(&self, task_id: &str) -> Result<(PathBuf, Option<String>, String)>;

    /// Auto-commit uncommitted changes in a copy. Returns true if a commit was created.
    pub fn commit_copy(&self, copy_path: &Path, message: &str) -> bool;

    /// Check if a copy has any file changes vs the base commit.
    pub fn has_changes(&self, copy_path: &Path, base_commit: Option<&str>) -> bool;

    /// Remove a copy directory.
    pub fn remove_copy(&self, copy_path: &Path) -> Result<()>;

    /// Fetch a worker's branch from a copy into the source repo.
    pub fn fetch_branch(&self, copy_path: &Path, branch: &str) -> Result<()>;

    /// Delete a branch from the source repo.
    pub fn delete_branch(&self, branch: &str) -> Result<()>;
}

pub struct GitIdentity {
    pub name: String,   // user.name
    pub email: String,  // user.email
}

# Source repo state:
HEAD=abc123 (on branch main)
Uncommitted: feature.rs (WIP)

# 1. Create copy for task-001
.enki/copies/task-001/  # CoW clone created (instant)
  # Contains: all source, build/, node_modules/, .git/, feature.rs
  # On branch: task/task-001

# 2. Worker runs, modifies files:
echo "impl" >> feature.rs
touch tests/test_feature.rs

# 3. Worker finishes, auto-commit:
git add -A
git commit -m "Implement feature"
# Now task-001 has 1 commit on task/task-001

# 4. Fetch branch to source:
cd <source>
git fetch .enki/copies/task-001 task/task-001:task/task-001
# Source now has branch task/task-001 with worker's commit

# 5. Refinery merges:
git merge task/task-001 --no-edit
# feature.rs and tests/test_feature.rs now in main

# 6. Cleanup:
rm -rf .enki/copies/task-001
git branch -D task/task-001