Replicate .claude/rules scaffolding from binect-js

Add the 9-file .claude/rules set (repo-identity, session-protocol,
first-session, workplan-convention, stack-and-commands, architecture,
repo-boundary, credential-routing, agents), adapted to binect-chrome:
slug, agent name, BCHROME-WP- workplan prefix, shared communication topic.
stack/architecture/repo-boundary filled with this repo's real content.

Rewrite CLAUDE.md to the @-import structure mirroring binect-js (prior
prose migrated into the rule files), retaining an inline Kaizen reference.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

.claude/rules/stack-and-commands.md

@@ -0,0 +1,29 @@
+## Stack
+
+- **Language:** TypeScript (Chrome Extension, Manifest V3)
+- **Key deps:** `@binect/js` (local `file:../binect-js` SDK — sibling repo must be present to build); Web Crypto API (AES-GCM credentials); Chrome APIs (`downloads`, `storage`, `alarms`, `activeTab`)
+- **Build/test tooling:** Webpack, Jest, ESLint, `tsc` (type-check only)
+
+## Dev Commands
+
+```bash
+# Install dependencies
+npm install
+
+# Build (production bundle → dist/)
+npm run build
+
+# Watch build for development
+npm run dev
+
+# Run tests
+npm test            # jest
+npm run test:watch  # jest --watch
+
+# Lint / type check
+npm run lint        # eslint src/**/*.{js,ts}
+npm run lint:fix    # eslint --fix
+npm run type-check  # tsc --noEmit
+```
+
+Load the unpacked extension from `dist/` via `chrome://extensions` (Developer mode) to test in-browser.