feat: scaffold OpenCode V2 toolkit with safe project installer

AGENTS.md

@@ -0,0 +1,40 @@
+# OpenCode Toolkit — Agent Instructions
+
+## Stack
+
+- TypeScript ESM package targeting Node.js 20+; initial runtime target is
+  OpenCode 2.0.24 and `@opencode/plugin` 2.0.24.
+- Tests use Node.js built-in `node:test`; coverage uses `c8`.
+- `jsonc-parser` edits project configuration while preserving comments.
+
+## Verified commands
+
+- Install dependencies: `npm install`
+- Compile: `npm run build`
+- Type check: `npm run typecheck`
+- Tests: `npm test` (builds first)
+- Coverage: `npm run test:coverage` (builds first; enforces 80% lines/functions)
+- Inspect package contents: `npm pack --dry-run`
+
+## Layout
+
+- `src/`: OpenCode V2 plugin, CLI, and project installer.
+- `content/`: curated skills and subagents copied into consuming projects.
+- `test/`: plugin contract and installer tests.
+- `docs/`: implementation plan and provenance records.
+
+## Conventions and gotchas
+
+- Use the V2 `@opencode/plugin` API; do not transplant ECC's V1 hook function.
+- Keep project installation conservative: never overwrite unmanaged or locally
+  modified files; preserve JSONC comments and unrelated configuration.
+- Keep state scoped by project/session. Do not introduce a mutable module-level
+  store for user session data.
+- Every imported ECC file must have source, revision, attribution, and hash
+  recorded in `docs/PROVENANCE.md`.
+- Tests do not prove provider-backed agent behavior; report that separately.
+- `npm test` compiles into ignored `dist/`; `npm pack --dry-run` runs the
+  `prepack` build hook and therefore writes generated output.
+
+See `docs/IMPLEMENTATION-PLAN.md`, `TODO.md`, and `FIXME.md` for scope and
+remaining work.