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/commands/code-review.md

@@ -1,40 +0,0 @@
-# Code Review
-
-Comprehensive security and quality review of uncommitted changes:
-
-1. Get changed files: git diff --name-only HEAD
-
-2. For each changed file, check for:
-
-**Security Issues (CRITICAL):**
-- Hardcoded credentials, API keys, tokens
-- SQL injection vulnerabilities
-- XSS vulnerabilities  
-- Missing input validation
-- Insecure dependencies
-- Path traversal risks
-
-**Code Quality (HIGH):**
-- Functions > 50 lines
-- Files > 800 lines
-- Nesting depth > 4 levels
-- Missing error handling
-- console.log statements
-- TODO/FIXME comments
-- Missing JSDoc for public APIs
-
-**Best Practices (MEDIUM):**
-- Mutation patterns (use immutable instead)
-- Emoji usage in code/comments
-- Missing tests for new code
-- Accessibility issues (a11y)
-
-3. Generate report with:
-   - Severity: CRITICAL, HIGH, MEDIUM, LOW
-   - File location and line numbers
-   - Issue description
-   - Suggested fix
-
-4. Block commit if CRITICAL or HIGH issues found
-
-Never approve code with security vulnerabilities!