Secure Input and Secret Handling

Adopt a consistent rule: anything coming from persistence, other platforms/accounts, terminal escape sequences, or secret-managed inputs must be validated/normalized and handled with collision-safe, non-injectable, non-leaky logic.

Apply this as standards:

• Path portability & sync safety: When persisting selections that may be synced, only mark as “syncable” if you can reliably interpret it under the current installation root. For custom theme paths, serialize as relative only when the absolute path is under the current themes_dir(). Preserve “foreign” absolute paths (don’t attempt partial cross-platform legacy inference).
• Test traversal + platform differences: Include unit tests for ../parent traversal behavior and add Windows-specific coverage where paths/roots differ.
• Shell command construction: Never interpolate user- or data-derived strings into shell commands without a quoting strategy. Use a single helper (e.g., POSIX-safe single-quote escaping) and route all shell-sensitive formatting through it.
• Secret injection precedence: When turning secrets into environment/config, define precedence and do not override worker-injected env vars. Insert typed auth secrets atomically, and skip on collisions to avoid unintended behavior or privilege changes.
• Secret file permissions: When writing secret-bearing config files, create parent dirs if needed and enforce restrictive permissions (e.g., 0o600) on Unix.
• Parsing hardening & logging: Avoid panics on malformed/unexpected structured input (use bounds checks/early exits). Don’t log raw untrusted substrings at debug/info levels if terminal/PTY content could contain echoed secrets.
• Endpoint/target allowlists: Prevent local-only configuration (e.g., local Ollama URLs) from being sent through remote/request settings.

Example patterns (condensed):

// 1) Shell quoting helper
fn shell_single_quote(value: &str) -> String {
    format!("'{}'", value.replace("'", "'\\''"))
}

// 2) Secret env insertion with collision safety
fn build_secret_env_vars(secrets: &HashMap<String, ManagedSecretValue>) -> HashMap<OsString, OsString> {
    let mut env_vars = HashMap::new();
    for (secret_key, secret) in secrets {
        // typed secrets: if any env var is already set non-empty, skip that secret entirely
        // (and never override existing process env)
        for (env_name, env_value) in typed_secret_entries(secret) {
            if std::env::var(env_name).is_ok_and(|v| !v.is_empty()) {
                continue; // collision: skip
            }
            env_vars.insert(OsString::from(env_name), OsString::from(env_value));
        }
    }
    env_vars
}