Add gmgn-wallet-score skill for wallet copy-trade scoring

Adds a new skill that scores any wallet address across three angles —
profitability (track-record score), copy-tradeability (score + a
latency/slippage/gas backtest), and Dev reputation for token-creator
wallets — plus trading-style tags, computed deterministically from
GMGN portfolio data. Wires it into CLAUDE.md's skill routing and the
Readme skill tables/install instructions, and refreshes the stale
plugin metadata descriptions/keywords to reflect all 8 current skills.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

.claude-plugin/plugin.json

@@ -1,13 +1,13 @@
 {
   "name": "gmgn-cli",
   "version": "1.0.0",
-  "description": "GMGN OpenAPI skills — token info, market data, wallet portfolio, and swap",
+  "description": "GMGN OpenAPI skills — token info, market data, wallet portfolio & copy-trade scoring, and swap",
   "author": {
     "name": "GMGN",
     "url": "https://gmgn.ai"
   },
   "repository": "https://github.com/GMGNAI/gmgn-skills",
   "license": "MIT",
-  "keywords": ["gmgn", "crypto", "solana", "token", "defi", "swap"],
+  "keywords": ["gmgn", "crypto", "solana", "token", "defi", "swap", "copytrade"],
   "skills": "./skills/"
 }