docs: use main ref in action snippet

[robotlearning123]

README GitHub Action example referenced @v1, but this repo does not publish a v1 tag yet. Switch to @main (with a note to pin to a tag/SHA) so the example works.

[github-actions]

Agent Ready Scan Results

Metric	Value
Level	L1
Score	56%
Project Type	cli
Passed	true

Full Report

Agent Readiness Report

Level: L1
Score: 56%
Project Type: cli

Pillar Summary

• docs: L3 (53%)
• style: L5 (100%)
• build: L5 (89%)
• test: L4 (50%)
• security: L5 (67%)
• observability: L5 (100%)
• env: L5 (100%)
• task_discovery: L5 (67%)
• product: L5 (100%)
• agent_config: L1 (36%)
• code_quality: L2 (0%)

Failed Checks

• [L1] agent_config.gitignore_agent: File exists but does not contain required pattern: .gitignore
• [L2] agent_config.claude_commands: Found 0 files matching '.claude/commands/*.md', need at least 1
• [L2] agent_config.cursorrules: Only 0/2 alternatives passed (need 1)
• [L2] agent_config.aider_config: Only 0/3 alternatives passed (need 1)
• [L2] agent_config.copilot_config: Only 0/2 alternatives passed (need 1)
• [L2] agent_config.windsurf_rules: File not found: .windsurfrules
• [L3] agent_config.mcp_json: Only 0/2 alternatives passed (need 1)
• [L3] agent_config.claude_hooks: Found 0 files matching '.claude/hooks/*', need at least 1
• [L4] agent_config.multi_agent_support: Only 0/3 alternatives passed (need 1)
• [L4] agent_config.context_injection: Only 0/3 alternatives passed (need 1)

...and 22 more