[task] Add cost and time estimates to Quick Start Prerequisites

[github-actions]

Objective

Add clear cost and time information to the Quick Start Prerequisites section to help beginners understand the commitment and costs involved.

Context

Documentation testing revealed beginners don't know:

• How much API access costs
• How long setup takes
• Whether they should use a test repo first

Related to #4257 (Documentation Noob Test Report)

Approach

Update docs/src/content/docs/setup/quick-start.mdx to add:

1. Time estimate section before prerequisites list
2. API Access costs section with all three options (GitHub Copilot, Claude, OpenAI)
3. Repository recommendation to start with test repository

Files to Modify

• docs/src/content/docs/setup/quick-start.mdx

Implementation Details

Add this content to the Prerequisites section:

**⏱️ Time Required:** ~15-30 minutes for initial setup

**💰 API Access (Choose One):**
- **GitHub Copilot CLI** (free with GitHub Copilot subscription)
- **Anthropic Claude API** (~$3-15 per workflow run, pay-as-you-go)
- **OpenAI API** (~$1-10 per workflow run, pay-as-you-go)

**🧪 Repository Recommendation:** Start with a test repository to understand costs and behavior before deploying to production repositories.

Acceptance Criteria

• Time estimate is visible before prerequisites list
• All three API options show cost information
• Test repository recommendation is clear
• Formatting follows existing documentation style (emojis optional, maintain consistency)
• Documentation builds without errors (npm run build in docs directory)

Priority

HIGH - Identified as Quick Win #1 with high impact for new users

AI generated by Plan Command for discussion #4257