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/rules/common-hooks.md

@@ -1,35 +0,0 @@
----
-description: "Hook system guidelines and TodoWrite best practices"
-alwaysApply: true
----
-
-# Hooks System
-
-## Hook Types
-
-- **PreToolUse**: Before tool execution (validation, parameter modification)
-- **PostToolUse**: After tool execution (auto-format, checks)
-- **Stop**: When session ends (final verification)
-
-## Auto-Accept Permissions
-
-Use with caution:
-- Enable for trusted, well-defined plans
-- Disable for exploratory work
-- Never use dangerously-skip-permissions flag
-- Configure `allowedTools` in `~/.claude.json` instead
-
-## TodoWrite Best Practices
-
-Use TodoWrite tool to:
-- Track progress on multi-step tasks
-- Verify understanding of instructions
-- Enable real-time steering
-- Show granular implementation steps
-
-Todo list reveals:
-- Out of order steps
-- Missing items
-- Extra unnecessary items
-- Wrong granularity
-- Misinterpreted requirements