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

commands/claw.md

@@ -0,0 +1,79 @@
+---
+description: Start the NanoClaw agent REPL — a persistent, session-aware AI assistant powered by the claude CLI.
+---
+
+# Claw Command
+
+Start an interactive AI agent session that persists conversation history to disk and optionally loads ECC skill context.
+
+## Usage
+
+```bash
+node scripts/claw.js
+```
+
+Or via npm:
+
+```bash
+npm run claw
+```
+
+## Environment Variables
+
+| Variable | Default | Description |
+|----------|---------|-------------|
+| `CLAW_SESSION` | `default` | Session name (alphanumeric + hyphens) |
+| `CLAW_SKILLS` | *(empty)* | Comma-separated skill names to load as system context |
+
+## REPL Commands
+
+Inside the REPL, type these commands directly at the prompt:
+
+```
+/clear      Clear current session history
+/history    Print full conversation history
+/sessions   List all saved sessions
+/help       Show available commands
+exit        Quit the REPL
+```
+
+## How It Works
+
+1. Reads `CLAW_SESSION` env var to select a named session (default: `default`)
+2. Loads conversation history from `~/.claude/claw/{session}.md`
+3. Optionally loads ECC skill context from `CLAW_SKILLS` env var
+4. Enters a blocking prompt loop — each user message is sent to `claude -p` with full history
+5. Responses are appended to the session file for persistence across restarts
+
+## Session Storage
+
+Sessions are stored as Markdown files in `~/.claude/claw/`:
+
+```
+~/.claude/claw/default.md
+~/.claude/claw/my-project.md
+```
+
+Each turn is formatted as:
+
+```markdown
+### [2025-01-15T10:30:00.000Z] User
+What does this function do?
+---
+### [2025-01-15T10:30:05.000Z] Assistant
+This function calculates...
+---
+```
+
+## Examples
+
+```bash
+# Start default session
+node scripts/claw.js
+
+# Named session
+CLAW_SESSION=my-project node scripts/claw.js
+
+# With skill context
+CLAW_SKILLS=tdd-workflow,security-review node scripts/claw.js
+```