feat: add OpenClaw skill definition for ClawHub publishing

Defines lightning-memory as an OpenClaw skill for agent-first distribution.
Includes all 7 MCP tools and installation instructions.
Update .gitignore to allow openclaw-skill/SKILL.md while keeping root SKILL.md ignored.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: 2 people

.gitignore

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 .pytest_cache/
 
 # Private/internal — not for public repo
-SKILL.md
+/SKILL.md
+!openclaw-skill/SKILL.md
 content/
 grants/
 marketing/

openclaw-skill/SKILL.md

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+---
+name: lightning-memory
+description: Decentralized agent memory with Nostr identity and Lightning L402 payments.
+version: 1.0.0
+requires_binaries: ["python3", "pip3"]
+requires_env: []
+---
+
+# Lightning Memory
+
+Decentralized agent memory for the Lightning economy. Store, query, and recall memories with cryptographic identity (Nostr) and micropayments (Lightning/L402).
+
+## Installation
+
+```bash
+pip3 install lightning-memory
+```
+
+No API keys required. Runs fully local by default. Optional Nostr relay sync and Lightning L402 gateway for decentralized/paid access.
+
+## What It Does
+
+AI agents can transact via Lightning (L402) but can't remember what they paid for, which vendors are reliable, or their spending patterns. Lightning Memory fixes this:
+
+- **Cryptographic identity** via Nostr keypairs — memories are signed and verifiable
+- **Semantic search** with local ONNX embeddings (no API calls)
+- **Nostr relay sync** — memories replicate across relays using NIP-78 events
+- **L402 payment gateway** — sell memory access via Lightning micropayments with macaroon auth
+- **MCP server** — works with Claude Code, Cursor, Windsurf, and any MCP client
+
+## MCP Tools (7 tools)
+
+| Tool | Purpose |
+|------|---------|
+| `store_memory` | Store a memory with content, tags, and metadata |
+| `query_memories` | Semantic search across stored memories |
+| `get_memory` | Retrieve a specific memory by ID |
+| `list_memories` | List recent memories with optional filters |
+| `delete_memory` | Remove a memory by ID |
+| `get_identity` | Get the current Nostr identity (npub) |
+| `sync_status` | Check Nostr relay sync status |
+
+## Quick Start
+
+```python
+from lightning_memory import MemoryStore
+
+store = MemoryStore()
+store.add("Vendor X charges 50 sats for image gen, quality 8/10")
+results = store.query("reliable image generation vendors")
+```
+
+## MCP Server
+
+```bash
+python -m lightning_memory.server
+```
+
+Or add to your MCP client config:
+```json
+{
+  "lightning-memory": {
+    "command": "python3",
+    "args": ["-m", "lightning_memory.server"]
+  }
+}
+```
+
+## Links
+
+- PyPI: https://pypi.org/project/lightning-memory/
+- GitHub: https://github.com/singularityjason/lightning-memory