feat: scaffold OpenCode V2 toolkit with safe project installer

TODO.md

@@ -0,0 +1,31 @@
+# TODO
+
+## First usable release
+
+- [x] Create an independent OpenCode V2 package and record the accepted plan.
+- [x] Import a small set of ECC skills and agent prompts with provenance.
+- [x] Implement the V2 plugin entry and read-only project-status tool.
+- [x] Add a project installer with collision and local-edit protection.
+- [x] Add uninstall behavior that preserves modified managed files.
+- [x] Add unit and installer regression tests and coverage threshold.
+- [x] Install the generated tarball in an isolated project and validate
+  idempotent CLI install/uninstall and native agent discovery.
+- [ ] Resolve why the OpenCode 2.0.24 standalone plugin API reports no active
+  plugin for the installed package; verify the custom tool is exposed.
+- [x] Detect and refuse ambiguous projects with both project config locations.
+- [ ] Evaluate support for multi-layer project config only after verifying V2
+  array merge and precedence behavior.
+- [x] Install the package tarball into a clean project outside this repository;
+  verify CLI idempotency and native agent discovery.
+- [ ] Add provider-backed verification after confirming credentials and model
+  usage budget with the user.
+- [ ] Confirm repository/package names and decide whether to publish.
+
+## Follow-up
+
+- [ ] Add a diagnostic command for installation state and supported versions.
+- [ ] Evaluate global/XDG installation only if project-local usage proves
+  insufficient.
+- [ ] Revisit memory and continuous-learning features as a separate design.
+- [ ] Review selected ECC content against a newer upstream SHA and update
+  [`docs/PROVENANCE.md`](docs/PROVENANCE.md) after any selective import.