feat: add skills system, hooks integration, and OpenAI-compatible provider

- Add skill system with types, registry, SkillTool, and 5 bundled skills
  (simplify, commit, review, debug, test)
- Integrate hooks into QueryEngine at 9 lifecycle points (SessionStart,
  UserPromptSubmit, PreToolUse, PostToolUse, PostToolUseFailure,
  PreCompact, PostCompact, Stop, SessionEnd)
- Add LLM provider abstraction supporting both Anthropic Messages API
  and OpenAI Chat Completions API (works with GPT, DeepSeek, Qwen, etc.)
- Add CODEANY_API_TYPE env var ('anthropic-messages' | 'openai-completions')
  with auto-detection from model name
- Remove all ANTHROPIC_* env var references, only support CODEANY_* prefix
- Add model pricing and context windows for OpenAI/DeepSeek models
- Remove direct @anthropic-ai/sdk dependency from all files except the
  Anthropic provider (types.ts, engine.ts, etc. are now provider-agnostic)
- Add PermissionBehavior type export
- Bump version to 0.2.0

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

package.json

@@ -12,7 +12,7 @@
   "bugs": {
     "url": "https://github.com/codeany-ai/open-agent-sdk-typescript/issues"
   },
-  "version": "0.1.0",
+  "version": "0.2.0",
   "description": "Open-source Agent SDK. Runs the full agent loop in-process — no local CLI required. Deploy anywhere: cloud, serverless, Docker, CI/CD.",
   "type": "module",
   "main": "./dist/index.js",