feat(ecc): prune plugin 43→12 items, promote 7 rules to .claude/rules/ (#245)

ECC community plugin pruning: removed 530+ non-essential files
(.cursor/, .opencode/, docs/ja-JP, docs/zh-CN, docs/zh-TW,
language-specific skills/agents/rules). Retained 4 agents,
3 commands, 5 skills. Promoted 13 rule files (8 common + 5
typescript) to .claude/rules/ for CC native loading. Extracted
reusable patterns to EXTRACTED-PATTERNS.md.

.cursor/mcp.json

@@ -1,70 +0,0 @@
-{
-  "mcpServers": {
-    "github": {
-      "command": "npx",
-      "args": ["-y", "@modelcontextprotocol/server-github"],
-      "env": {
-        "GITHUB_PERSONAL_ACCESS_TOKEN": "${env:GITHUB_PERSONAL_ACCESS_TOKEN}"
-      }
-    },
-    "firecrawl": {
-      "command": "npx",
-      "args": ["-y", "firecrawl-mcp"],
-      "env": {
-        "FIRECRAWL_API_KEY": "${env:FIRECRAWL_API_KEY}"
-      }
-    },
-    "supabase": {
-      "command": "npx",
-      "args": ["-y", "@supabase/mcp-server-supabase@latest", "--project-ref=YOUR_PROJECT_REF"]
-    },
-    "memory": {
-      "command": "npx",
-      "args": ["-y", "@modelcontextprotocol/server-memory"]
-    },
-    "sequential-thinking": {
-      "command": "npx",
-      "args": ["-y", "@modelcontextprotocol/server-sequential-thinking"]
-    },
-    "vercel": {
-      "type": "http",
-      "url": "https://mcp.vercel.com"
-    },
-    "railway": {
-      "command": "npx",
-      "args": ["-y", "@railway/mcp-server"]
-    },
-    "cloudflare-docs": {
-      "type": "http",
-      "url": "https://docs.mcp.cloudflare.com/mcp"
-    },
-    "cloudflare-workers-builds": {
-      "type": "http",
-      "url": "https://builds.mcp.cloudflare.com/mcp"
-    },
-    "cloudflare-workers-bindings": {
-      "type": "http",
-      "url": "https://bindings.mcp.cloudflare.com/mcp"
-    },
-    "cloudflare-observability": {
-      "type": "http",
-      "url": "https://observability.mcp.cloudflare.com/mcp"
-    },
-    "clickhouse": {
-      "type": "http",
-      "url": "https://mcp.clickhouse.cloud/mcp"
-    },
-    "context7": {
-      "command": "npx",
-      "args": ["-y", "@context7/mcp-server"]
-    },
-    "magic": {
-      "command": "npx",
-      "args": ["-y", "@magicuidesign/mcp@latest"]
-    },
-    "filesystem": {
-      "command": "npx",
-      "args": ["-y", "@modelcontextprotocol/server-filesystem", "/path/to/your/projects"]
-    }
-  }
-}