feat: add the inline tag and json-style omitempty

Assisted-by: GLM 5.3 Flash

CHANGELOG.md

@@ -94,6 +94,15 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Changed
 
+- `omitempty` follows the encoding/json semantics: the field is skipped when
+  it holds an empty string, a zero number, `false`, a nil pointer or
+  interface, or a nil or empty slice, array or map. In 1.x the option covered
+  only the collections.
+- The `toml` tag gained the `inline` option: a struct or map field tagged
+  `toml:"retry,inline"` emits as `retry = {…}` instead of a header section,
+  whatever its size, a named embedded struct included. Forcing it on an array
+  of tables is an error, because the inline form would re-parse as a value
+  array and change the value's Go type.
 - The output takes the TOML 1.1 form. A date-time writes its seconds only when
   the value carries them and drops the trailing zeros of a fractional second,
   so `07:32:00` is written `07:32` and half a second as `00.5`. Both are the