refactor(deep-research): replace case study company with ByteDance example

Replace \"深度推理（上海）科技有限公司\" with \"字节跳动子公司\"
as the case study example to avoid exposing user's own company info.

Also update .gitignore to exclude:
- deep-research-output/ (contains sensitive research data)
- recovered_deep_research/
- .opencli/
- douban-skill/ (work-in-progress)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.gitignore

@@ -82,3 +82,13 @@ INSTALLATION.md
 seo-expert/
 video-creator/
 /jsonl-viewer/
+
+# Research output (may contain sensitive data)
+deep-research-output/
+recovered_deep_research/
+
+# OpenCLI cache
+.opencli/
+
+# Work-in-progress skills
+douban-skill/

deep-research/SKILL.md

@@ -320,7 +320,7 @@ Report: `[P3 complete] {approved}/{total} sources. {N} domains. Official share:
 
 ### Handling Information Black Box
 
-When researching entities with no public footprint (like the "深度推理" example):
+When researching entities with no public footprint (like the "字节跳动子公司" example):
 
 **What an external researcher would find:**
 - WHOIS: Privacy protected → No owner info

deep-research/references/V6_1_improvements.md

@@ -2,7 +2,7 @@
 
 **Date**: 2026-04-03  
 **Version**: 2.3.0 → 2.4.0  
-**Based on**: User feedback and "深度推理" case study
+**Based on**: User feedback and "字节跳动" case study
 
 ---
 
@@ -18,7 +18,7 @@ The problem is not using user's private information—it's **circular verificati
 
 **Example of the Error**:
 ```
-User: "Research my company 深度推理"
+User: "Research my company 字节跳动子公司"
 ❌ WRONG: Access user's Spaceship → "You own 25 domains"
    → This is circular: user already knows they own these domains
 

deep-research/references/source_accessibility_policy.md

@@ -7,10 +7,10 @@
 
 ## The Problem
 
-In the "深度推理" case study, we made a **methodology error**:
+In the "字节跳动" case study, we made a **methodology error**:
 
 **What happened**:
-1. User asked to research **their own company**: "深度推理（上海）科技有限公司"
+1. User asked to research **their own company**: "字节跳动某子公司"
 2. We accessed user's **own Spaceship account** (their private registrar)
 3. Found 25 domains **the user already owned**
 4. Reported back: "The company owns these 25 domains"
@@ -60,7 +60,7 @@ When researching **third parties** (competitors, markets, investments):
 ## The Distinction
 
 ```
-Research Target: 深度推理（上海）科技有限公司
+Research Target: 字节跳动某子公司
 ├─ Is this the user's own company? → YES
 ├─ Can we use user's private data about it? → NO (circular)
 └─ Must rely on: Public sources only
@@ -80,7 +80,7 @@ Research Target: 竞争对手公司 X
 **Approach**: External investigator perspective
 
 ```
-User: "Research my company 深度推理"
+User: "Research my company 字节跳动子公司"
 
 CORRECT RESPONSE:
 1. Search public sources (WHOIS, web, news)