feat: enhance session sync and add voice input feature

- 增强会话同步：确保所有会话完全同步到新账号
  - 强制更新 model_provider 字段
  - 添加 session_index.jsonl 重建功能
  - 确保数据库 UPSERT 逻辑正确处理所有情况
- 新增语音输入功能（voice_cdp.js, voice_inject.js）
- 测试脚本和增强模块

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

.learnings/ERRORS.md

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+# Errors
+
+Command failures and integration errors.
+
+---
+
+## [ERR-20260716-001] tavily_skill_local_setup
+
+**Logged**: 2026-07-16T17:27:46+0800
+**Priority**: medium
+**Status**: pending
+**Area**: config
+
+### Summary
+Local Tavily skill script could not run directly and its Python dependency was not installed.
+
+### Error
+```text
+permission denied: .../Tavily-AI-Search/scripts/tavily_search.py
+tavily-python package not installed
+externally-managed-environment
+```
+
+### Context
+- Attempted to use the Tavily skill for a news search.
+- The script lacks executable permission, so `python3 script.py` is needed.
+- Installing `tavily-python` into the system Python was blocked by PEP 668.
+- `TAVILY_API_KEY` was not present in the environment.
+
+### Suggested Fix
+Use a project or skill-local virtual environment for `tavily-python`, make the script executable if desired, and configure `TAVILY_API_KEY` or a supported app config key.
+
+### Metadata
+- Reproducible: yes
+- Related Files: /Users/mac/Library/Application Support/tokendun-codex-client/skills/Tavily-AI-Search/scripts/tavily_search.py
+
+---

.learnings/FEATURE_REQUESTS.md

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+# Feature Requests
+
+Capabilities requested by the user.
+
+---

.learnings/LEARNINGS.md

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+# Learnings
+
+Corrections, insights, and knowledge gaps captured during development.
+
+**Categories**: correction | insight | knowledge_gap | best_practice
+
+---