feat: add NanoClaw agent REPL — persistent session-aware CLI for ECC

Implements a barebones agent loop that delegates to `claude -p` with
markdown-as-database session persistence and ECC skill context loading.
Zero external dependencies, ~264 lines of pure Node.js CommonJS.

- scripts/claw.js: core module (storage, context, delegation, REPL)
- commands/claw.md: slash command definition with usage docs
- tests/scripts/claw.test.js: 14 unit tests covering all modules
- package.json: add claw script and files entry
- tests/run-all.js: register claw tests in test manifest

tests/run-all.js

@@ -20,6 +20,7 @@ const testFiles = [
   'hooks/suggest-compact.test.js',
   'integration/hooks.test.js',
   'ci/validators.test.js',
+  'scripts/claw.test.js',
   'scripts/setup-package-manager.test.js',
   'scripts/skill-create-output.test.js'
 ];