docs(agent-development): improve visibility of tools vs allowed-tools disambiguation

[sjnims]

Problem

The important distinction between tools (for agents) and allowed-tools (for skills) is buried at the bottom of the Quick Reference section in SKILL.md:

> **Note:** Agents use `tools` to restrict tool access. Skills use `allowed-tools` for the same purpose. The field names differ between component types.

This is critical disambiguating information that users frequently need when switching between writing agents and skills. Its current placement makes it easy to miss.

Current Location

SKILL.md line ~385 (bottom of Quick Reference table, as a note)

Recommended Fix

Option A: Move to Frontmatter Fields section

Add under the tools field documentation (around line 150):

### tools (optional)

Restrict agent to specific tools.

> **Important:** Agents use `tools` while Skills use `allowed-tools`. The field names differ between component types.

**Format:** Array of tool names
...

Option B: Add callout box in Overview

Add prominent callout early in the document:

## Overview

...

> **⚠️ Field Name Difference:** Agents use `tools` to restrict tool access. Skills use `allowed-tools` for the same purpose. Don't confuse these when switching between component types.

Option C: Both locations

Include in both the Overview (as a warning callout) and the tools field documentation (as context).

Acceptance Criteria

• tools vs allowed-tools distinction is visible early in the document OR prominently in the tools field section
• Users creating agents won't accidentally use allowed-tools
• Cross-reference to skill-development skill for allowed-tools usage (optional)

Files to Modify

• plugins/plugin-dev/skills/agent-development/SKILL.md

[sjnims]

PR submitted: #28