add CHANGELOG.md for v0.1.0 release

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: mtingers

CHANGELOG.md

@@ -0,0 +1,18 @@
+# Changelog
+
+## v0.1.0 — 2026-03-15
+
+Initial release. Drop-in replacement for [fatih/structs](https://github.com/fatih/structs) with modern Go improvements.
+
+### Added
+
+- Core `Struct` type with `New()` constructor and functional options (`WithTag`)
+- Conversion methods: `Map()`, `Values()`, `Names()`, `Fields()`
+- `Field` type with `Name`, `Value`, `Kind`, `Tag`, `IsZero`, `IsExported`, `IsEmbedded`, `Set`, nested `Fields`
+- Tag parsing: `omitempty`, `-`, `omitnested`, `string` options
+- Compatibility layer: `FillMap()` for fatih/structs migration
+- Error returns instead of panics (`ErrFieldNotFound`, `ErrNotExported`, `ErrNotSettable`, `ErrTypeMismatch`)
+- Nil pointer safety for embedded/nested structs
+- Top-level convenience functions: `Map`, `Values`, `Names`, `Fields`, `IsZero`, `HasZero`, `IsStruct`, `Name`
+- 96.5% test coverage with 60+ tests
+- CI on Go 1.23 and 1.24 with golangci-lint