feat: add bilingual support (zh/en) for research skills

- Rename skills/research to skills/research-en (English version)
- Add skills/research-zh (Chinese version with SKILL.md structure)
- Update README.md with bilingual documentation
- Add web-search-agent.md

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

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

skills/research-en/add-fields/SKILL.md

@@ -0,0 +1,30 @@
+---
+description: Add field definitions to existing research outline.
+allowed-tools: Bash, Read, Write, Glob, WebSearch, Task, AskUserQuestion
+---
+
+# Research Add Fields - Supplement Research Fields
+
+## Trigger
+`/research-add-fields`
+
+## Workflow
+
+### Step 1: Auto-locate Fields File
+Find `*/fields.yaml` file in current working directory, auto-read existing fields definitions.
+
+### Step 2: Get Supplement Source
+Ask user to choose:
+- **A. User direct input**: User provides field names and descriptions
+- **B. Web Search**: Launch agent to search common fields in this domain
+
+### Step 3: Display and Confirm
+- Display suggested new fields list
+- User confirms which fields to add
+- User specifies field category and detail_level
+
+### Step 4: Save Update
+Append confirmed fields to fields.yaml, save file.
+
+## Output
+Updated `{topic}/fields.yaml` file (in-place modification, requires user confirmation)