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.

.opencode/commands/update-codemaps.md

@@ -1,81 +0,0 @@
----
-description: Update codemaps for codebase navigation
-agent: doc-updater
-subtask: true
----
-
-# Update Codemaps Command
-
-Update codemaps to reflect current codebase structure: $ARGUMENTS
-
-## Your Task
-
-Generate or update codemaps in `docs/CODEMAPS/` directory:
-
-1. **Analyze codebase structure**
-2. **Generate component maps**
-3. **Document relationships**
-4. **Update navigation guides**
-
-## Codemap Types
-
-### Architecture Map
-```
-docs/CODEMAPS/ARCHITECTURE.md
-```
-- High-level system overview
-- Component relationships
-- Data flow diagrams
-
-### Module Map
-```
-docs/CODEMAPS/MODULES.md
-```
-- Module descriptions
-- Public APIs
-- Dependencies
-
-### File Map
-```
-docs/CODEMAPS/FILES.md
-```
-- Directory structure
-- File purposes
-- Key files
-
-## Codemap Format
-
-### [Module Name]
-
-**Purpose**: [Brief description]
-
-**Location**: `src/[path]/`
-
-**Key Files**:
-- `file1.ts` - [purpose]
-- `file2.ts` - [purpose]
-
-**Dependencies**:
-- [Module A]
-- [Module B]
-
-**Exports**:
-- `functionName()` - [description]
-- `ClassName` - [description]
-
-**Usage Example**:
-```typescript
-import { functionName } from '@/module'
-```
-
-## Generation Process
-
-1. Scan directory structure
-2. Parse imports/exports
-3. Build dependency graph
-4. Generate markdown maps
-5. Validate links
-
----
-
-**TIP**: Keep codemaps updated when adding new modules or significant refactoring.