Function warn_deprecated_dockerfiles

src/assets/mod.rs:22–60

Check for deprecated filesystem-based dockerfile directories and warn the user. Previously, TSK loaded custom dockerfiles from `.tsk/dockerfiles/` and `~/.config/tsk/dockerfiles/`. These are now replaced by inline config fields (`setup`, `stack_config`, `agent_config`) in `tsk.toml`.

(project_root: Option<&Path>, tsk_env: &TskEnv)

/// `~/.config/tsk/dockerfiles/`. These are now replaced by inline config fields
/// (`setup`, `stack_config`, `agent_config`) in `tsk.toml`.
pub fn warn_deprecated_dockerfiles(project_root: Option<&Path>, tsk_env: &TskEnv) {
    let paths: Vec<(&str, std::path::PathBuf)> = [
        (
            ".tsk/tsk.toml",
            project_root.map(|r| r.join(".tsk").join("dockerfiles")),
        ),
        (
            "~/.config/tsk/tsk.toml",
            Some(tsk_env.config_dir().join("dockerfiles")),
        ),
    ]
    .into_iter()
    .filter_map(|(config, path)| path.map(|p| (config, p)))
    .filter(|(_, path)| path.exists())
    .collect();

    for (config_location, path) in paths {
        let mut layers = Vec::new();
        if path.join("project").exists() {
            layers.push("  - project/*.dockerfile → `setup` field");
        }
        if path.join("stack").exists() {
            layers.push("  - stack/*.dockerfile   → `[stack_config.<name>]` setup field");
        }
        if path.join("agent").exists() {
            layers.push("  - agent/*.dockerfile   → `[agent_config.<name>]` setup field");
        }
        eprintln!(
            "\x1b[31mWarning: Found removed dockerfile directory: {}\x1b[0m\n\
             Filesystem-based Docker layers have been removed and are no longer loaded.\n\
             Migrate to inline config in {}:\n\
             {}\n\
             See the README for the new configuration format.",
            path.display(),
            config_location,
            layers.join("\n"),
        );
    }
}

/// Find a template by name, checking project, user, and embedded sources in priority order.
pub fn find_template(name: &str, project_root: Option<&Path>, tsk_env: &TskEnv) -> Result<String> {