📝 Add sync config export API docs

docs/api/text-formatter-config-to-json.md

@@ -0,0 +1,99 @@
+---
+name: text-formatter-config-to-json
+group: api
+category: config
+update-time: 20260512
+description: Convert TextFormatterConfig into a JSON value for formatter export, persistence, or generated config output.
+key-word:
+    - formatter
+    - config
+    - json
+    - public
+---
+
+## Text-formatter-config-to-json
+
+Convert a typed `TextFormatterConfig` into a `JsonValue`. This helper exports formatter toggles, separators, color settings, markup behavior, and optional style tags in a machine-readable form.
+
+### Interface
+
+```moonbit
+pub fn text_formatter_config_to_json(config : TextFormatterConfig) -> @json_parser.JsonValue {}
+```
+
+#### input
+
+- `config : TextFormatterConfig` - Formatter configuration to export.
+
+#### output
+
+- `JsonValue` - Structured JSON representation of the formatter config.
+
+---
+
+e.g.:
+```moonbit
+pub fn text_formatter_config_to_json(config : TextFormatterConfig) -> @json_parser.JsonValue {}
+```
+
+#### input
+
+- `config : TextFormatterConfig` - Typed formatter config.
+
+#### output
+
+- `JsonValue` - JSON-exportable formatter object.
+
+---
+
+### Explanation
+
+Detailed rules explaining key parameters and behaviors
+
+- The output includes visibility flags, separators, template, color settings, and markup settings.
+- `style_tags` is exported only when the map is not empty.
+- Enum-like formatter options are serialized using their stable label strings.
+- The JSON shape matches the formatter section accepted by config parsing.
+
+### How to Use
+
+Here are some specific examples provided.
+
+#### When Need Structured Formatter Export
+
+When formatter config should be embedded inside a larger config object:
+```moonbit
+let value = text_formatter_config_to_json(TextFormatterConfig::new(show_target=false))
+```
+
+In this example, callers can compose the JSON value without re-implementing serialization.
+
+#### When Need To Persist Formatter Settings
+
+When generated formatter policy should be stored or inspected:
+```moonbit
+let formatter_json = text_formatter_config_to_json(
+  TextFormatterConfig::new(separator=" | ", template="[{level}] {message}"),
+)
+```
+
+In this example, the config becomes transport-friendly structured data.
+
+### Error Case
+
+e.g.:
+- If `style_tags` is empty, the field is omitted instead of being emitted as an empty object.
+
+- If callers need immediate text output rather than a JSON value, they should use `stringify_text_formatter_config(...)` instead.
+
+### Notes
+
+Notes are here.
+
+1. This helper exports formatter configuration, not rendered log output.
+
+2. Use it when downstream code expects `JsonValue`.
+
+3. Pair it with `TextFormatterConfig::new(...)` for code-generated formatter policies.
+
+4. The output is compatible with config roundtrip workflows.