fix: narrow chrome extension scope for faster store review

[hanneshapke]

Summary

• Remove redundant activeTab permission (already covered by explicit host permissions)
• Add perplexity.ai to default AI service domains in manifest and config
• Add localhost and 127.0.0.1 to host_permissions for local proxy connectivity
• Strip console.log calls that dumped PII detection results and backend URLs — reviewers run extensions and scan the console

Test plan

• Load unpacked extension and verify it activates on all listed AI chat sites
• Verify PII detection modal still works on ChatGPT, Claude, Gemini
• Confirm no PII data appears in the browser console during detection
• Test custom domain addition via options page still works

🤖 Generated with Claude Code