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.

rules/golang/hooks.md

@@ -1,17 +0,0 @@
----
-paths:
-  - "**/*.go"
-  - "**/go.mod"
-  - "**/go.sum"
----
-# Go Hooks
-
-> This file extends [common/hooks.md](../common/hooks.md) with Go specific content.
-
-## PostToolUse Hooks
-
-Configure in `~/.claude/settings.json`:
-
-- **gofmt/goimports**: Auto-format `.go` files after edit
-- **go vet**: Run static analysis after editing `.go` files
-- **staticcheck**: Run extended static checks on modified packages