Function fallback_sanitize_yaml

crates/opencode-config/src/loader.rs:774–817

Fallback sanitization for invalid YAML frontmatter. Matches TS `ConfigMarkdown.fallbackSanitization`: if a top-level value contains a colon (which confuses simple YAML parsers), convert it to a block scalar so the value is preserved verbatim.

(yaml: &str)

/// contains a colon (which confuses simple YAML parsers), convert it to a
/// block scalar so the value is preserved verbatim.
fn fallback_sanitize_yaml(yaml: &str) -> String {
    let mut result: Vec<String> = Vec::new();
    for line in yaml.lines() {
        let trimmed = line.trim();
        // Pass through comments and empty lines
        if trimmed.starts_with('#') || trimmed.is_empty() {
            result.push(line.to_string());
            continue;
        }
        // Pass through continuation/indented lines
        if line.starts_with(char::is_whitespace) {
            result.push(line.to_string());
            continue;
        }
        // Match top-level key: value
        let kv_re = regex::Regex::new(r"^([a-zA-Z_][a-zA-Z0-9_]*)\s*:\s*(.*)$").unwrap();
        let Some(caps) = kv_re.captures(line) else {
            result.push(line.to_string());
            continue;
        };
        let key = &caps[1];
        let value = caps[2].trim();
        // Skip if value is empty, already quoted, or uses block scalar indicator
        if value.is_empty()
            || value == ">"
            || value == "|"
            || value == "|-"
            || value == ">-"
            || value.starts_with('"')
            || value.starts_with('\'')
        {
            result.push(line.to_string());
            continue;
        }
        // If value contains a colon, convert to block scalar
        if value.contains(':') {
            result.push(format!("{}: |-", key));
            result.push(format!("  {}", value));
            continue;
        }
        result.push(line.to_string());
    }
    result.join("\n")
}

/// Parse a YAML scalar value string into a JSON value.
fn yaml_scalar_to_json(value: &str) -> serde_json::Value {