docs: backfill CHANGELOG with 0.1.0-0.1.4 history

CHANGELOG.md

@@ -2,10 +2,47 @@
 
 All notable changes to this project are documented in this file.
 
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
 ## [0.1.4]
 
 ### Added
 - `view` command now renders RFC content through an external Markdown renderer
   when the `RFC_VIEWER` environment variable is set (content is piped on stdin),
   mirroring how `edit` uses `$EDITOR` (RFC-0009).
 - `--raw` flag for `view` to force raw Markdown output, ignoring `RFC_VIEWER`.
+
+## [0.1.3]
+
+### Added
+- Git-based drift detection for the `doctor` command: `--drift git` (default)
+  compares RFC and linked-file freshness using git commit time, with
+  `--drift mtime` available as a fallback (RFC-0008).
+
+## [0.1.2]
+
+### Added
+- Shell completion generation via the `completions <shell>` command.
+- Status transition validation: `set` enforces the allowed RFC lifecycle
+  (draft -> review -> accepted -> implemented, plus superseded/deprecated).
+
+## [0.1.1]
+
+### Changed
+- Translated CLI help output to English.
+- Added an English `README.md`; the Russian version moved to `README_ru.md`.
+
+## [0.1.0]
+
+### Added
+- Initial RFC workflow and CLI bootstrap (RFC-0001).
+- `init` and `new` commands to scaffold the RFC structure and create RFCs
+  (RFC-0002).
+- `list`, `view`, `status`, and `edit` commands for reading and navigating RFCs
+  (RFC-0003).
+- `set`, `check`, and `reindex` commands for status changes, validation, and
+  index rebuilds (RFC-0004).
+- `link`, `unlink`, and `deps` commands to connect RFCs with source files and
+  inspect dependencies (RFC-0005).
+- `doctor` command for repository health diagnostics (RFC-0006).