2.0.0 — packaging & structure major: skills-only plugin, release-based artifacts

Memory behavior unchanged; the major signals a distribution/install break.

- Legacy commands/ directory DELETED (skills-only; the 1.6.0 skills were verified
  on desktop + CoWork and already took precedence). Pre-skills clients install
  1.6.0 from the release history.
- Artifact policy: the repo tracks only the echo-memory.plugin pointer; the 15
  historical versioned zips leave the tree (git history retains them); versioned
  builds ship as Gitea release assets, one release per v<version> tag, starting
  v2.0.0. .gitignore: *.plugin except the pointer.
- README: post-2.0 repository layout; "packaging for other agent runtimes" note
  (ports are build targets from the canonical tree, never a second source tree).
- ROADMAP-2.0 items ticked; manifest -> 2.0.0.

All suites green (25/25 unit + 4 e2e suites); artifact rebuilt skills-only
(79 entries, no commands/).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

CHANGELOG.md

@@ -1,5 +1,36 @@
 # Changelog
 
+## 2.0.0
+
+**Packaging & structure major — nothing about memory behavior changes.** The major
+version signals "reinstall, re-clone expectations": how the plugin is distributed
+and installed is what breaks.
+
+### Removed — the legacy `commands/` directory (BREAKING for pre-skills clients)
+
+The plugin is **skills-only**. The eight `/echo-*` entry points live exclusively at
+`skills/<name>/SKILL.md` (introduced 1.6.0, verified on desktop + CoWork
+2026-07-28, where they already took precedence). A Claude Code old enough to lack
+skills support loses the slash commands — install 1.6.0 from the release history
+instead.
+
+### Changed — artifact policy (BREAKING for anyone pulling zips from the repo)
+
+- The repo tracks **only** `echo-memory.plugin` (the current installable). The 15
+  historical `echo-memory-<version>.plugin` zips are deleted from the tree (git
+  history retains them).
+- Versioned builds are published as **Gitea releases** on
+  `git.alwisp.com/jason/echo` — one release per `v<version>` tag, artifact
+  attached, starting with `v2.0.0`.
+- `.gitignore` now ignores `*.plugin` except the pointer.
+
+### Added — "packaging for other agent runtimes" README note
+
+The retired Codex tree stays retired; the README now documents what a port needs
+(manifest shape, skill entry point, script invocation + hooks) and the rule that a
+port must be a **build target** from the canonical source tree, never a second
+hand-maintained copy.
+
 ## 1.6.0
 
 ### Changed — the eight slash commands migrated to the skills format