feat: implement enterprise workflow with multi-backend support

## Overview
Complete implementation of enterprise-level workflow features including
multi-backend execution (Codex/Claude/Gemini), GitHub issue-to-PR automation,
hooks system, and comprehensive documentation.

## Major Changes

### 1. Multi-Backend Support (codeagent-wrapper)
- Renamed codex-wrapper → codeagent-wrapper
- Backend interface with Codex/Claude/Gemini implementations
- Multi-format JSON stream parser (auto-detects backend)
- CLI flag: --backend codex|claude|gemini (default: codex)
- Test coverage: 89.2%

**Files:**
- codeagent-wrapper/backend.go - Backend interface
- codeagent-wrapper/parser.go - Multi-format parser
- codeagent-wrapper/config.go - CLI parsing with backend selection
- codeagent-wrapper/executor.go - Process execution
- codeagent-wrapper/logger.go - Async logging
- codeagent-wrapper/utils.go - Utilities

### 2. GitHub Workflow Commands
- /gh-create-issue - Create structured issues via guided dialogue
- /gh-implement - Issue-to-PR automation with full dev lifecycle

**Files:**
- github-workflow/commands/gh-create-issue.md
- github-workflow/commands/gh-implement.md
- skills/codeagent/SKILL.md

### 3. Hooks System
- UserPromptSubmit hook for skill activation
- Pre-commit example with code quality checks
- merge_json operation in install.py for settings.json merging

**Files:**
- hooks/skill-activation-prompt.sh|.js
- hooks/pre-commit.sh
- hooks/hooks-config.json
- hooks/test-skill-activation.sh

### 4. Skills System
- skill-rules.json for auto-activation
- codeagent skill for multi-backend wrapper

**Files:**
- skills/skill-rules.json
- skills/codeagent/SKILL.md
- skills/codex/SKILL.md (updated)

### 5. Installation System
- install.py: Added merge_json operation
- config.json: Added "gh" module
- config.schema.json: Added op_merge_json schema

### 6. CI/CD
- GitHub Actions workflow for testing and building

**Files:**
- .github/workflows/ci.yml

### 7. Comprehensive Documentation
- Architecture overview with ASCII diagrams
- Codeagent-wrapper complete usage guide
- GitHub workflow detailed examples
- Hooks customization guide

**Files:**
- docs/architecture.md (21KB)
- docs/CODEAGENT-WRAPPER.md (9KB)
- docs/GITHUB-WORKFLOW.md (9KB)
- docs/HOOKS.md (4KB)
- docs/enterprise-workflow-ideas.md
- README.md (updated with doc links)

## Test Results
- All tests passing ✅
- Coverage: 89.2%
- Security scan: 0 issues (gosec)

## Breaking Changes
- codex-wrapper renamed to codeagent-wrapper
- Default backend: codex (documented in README)

## Migration Guide
Users with codex-wrapper installed should:
1. Run: python3 install.py --module dev --force
2. Update shell aliases if any

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

hooks/skill-activation-prompt.js

@@ -0,0 +1,85 @@
+#!/usr/bin/env node
+
+const fs = require("fs");
+const path = require("path");
+
+function readInput() {
+  const raw = fs.readFileSync(0, "utf8").trim();
+  if (!raw) return {};
+  try {
+    return JSON.parse(raw);
+  } catch (_err) {
+    return {};
+  }
+}
+
+function extractPrompt(payload) {
+  return (
+    payload.prompt ||
+    payload.text ||
+    payload.userPrompt ||
+    (payload.data && payload.data.prompt) ||
+    ""
+  ).toString();
+}
+
+function loadRules() {
+  const rulesPath = path.resolve(__dirname, "../skills/skill-rules.json");
+  try {
+    const file = fs.readFileSync(rulesPath, "utf8");
+    return JSON.parse(file);
+  } catch (_err) {
+    return { skills: {} };
+  }
+}
+
+function matchSkill(prompt, rule, skillName) {
+  const triggers = (rule && rule.promptTriggers) || {};
+  const keywords = [...(triggers.keywords || []), skillName].filter(Boolean);
+  const patterns = triggers.intentPatterns || [];
+  const promptLower = prompt.toLowerCase();
+
+  const keyword = keywords.find((k) => promptLower.includes(k.toLowerCase()));
+  if (keyword) {
+    return `命中关键词 "${keyword}"`;
+  }
+
+  for (const pattern of patterns) {
+    try {
+      if (new RegExp(pattern, "i").test(prompt)) {
+        return `命中模式 /${pattern}/`;
+      }
+    } catch (_err) {
+      continue;
+    }
+  }
+  return null;
+}
+
+function main() {
+  const payload = readInput();
+  const prompt = extractPrompt(payload);
+  if (!prompt.trim()) {
+    console.log(JSON.stringify({ suggestedSkills: [] }, null, 2));
+    return;
+  }
+
+  const rules = loadRules();
+  const suggestions = [];
+
+  for (const [name, rule] of Object.entries(rules.skills || {})) {
+    const matchReason = matchSkill(prompt, rule, name);
+    if (matchReason) {
+      suggestions.push({
+        skill: name,
+        enforcement: rule.enforcement || "suggest",
+        priority: rule.priority || "normal",
+        reason: matchReason
+      });
+    }
+  }
+
+  console.log(JSON.stringify({ suggestedSkills: suggestions }, null, 2));
+}
+
+main();