fix(agent-development): replace emoji with text in SKILL.md warning callout

[sjnims]

Summary

The agent-development SKILL.md uses an emoji (⚠️) in a warning callout, which conflicts with the project's style guideline to avoid emojis unless explicitly requested.

Severity: Minor (style guideline compliance)

Problem

From CLAUDE.md user instructions:

Only use emojis if the user explicitly requests it. Avoid using emojis in all communication unless asked.

While this primarily applies to Claude's responses, documentation should also follow consistent style guidelines.

Current State

> **⚠️ Field Name Difference:** Agents use `tools` to restrict tool access. Skills use `allowed-tools` for the same purpose.

Expected State

> **Important - Field Name Difference:** Agents use `tools` to restrict tool access. Skills use `allowed-tools` for the same purpose.

Or alternatively:

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

Location

• File: plugins/plugin-dev/skills/agent-development/SKILL.md
• Line: 17

Acceptance Criteria

• ⚠️ emoji removed from SKILL.md
• Warning/important context preserved with text alternative
• Meaning and visibility of the callout maintained

[sjnims]

PR submitted: #37