Add comprehensive tooltips to every field in cache analysis run panel

[Copilot]

This PR adds comprehensive tooltips to every piece of information displayed in the run panel, providing users with clear technical definitions and links to relevant documentation.

🎯 Changes Made

✨ New Features

• Comprehensive tooltip coverage for all cache analysis fields
• RFC 9211 compliant definitions for forward reason values (bypass, method, uri-miss, vary-miss, miss, request, stale, partial)
• Special handling for known cache types:
  • Netlify Edge → Links to Netlify caching documentation
  • Netlify Durable → Links to Netlify caching documentation
  • Next.js → Links to Next.js Full Route Cache documentation
  • Unknown caches → Generic third-party cache descriptions
• Documentation links for Netlify-specific features like Netlify-Vary header

📋 Tooltip Coverage

All fields now have tooltips with technical definitions:

Infrastructure:

• Served by, CDN node(s)

Cache Status Parameters:

• Hit, Forwarded because (with RFC 9211 value definitions), Forwarded status, TTL, Stored the response, Collapsed requests, Cache key, Extra details

Response Headers:

• Cacheable, Age, Date, ETag, Expires at, TTL (browser/CDN/Netlify CDN), Vary, Netlify-Vary, Revalidation

🏗️ Implementation Details

• Created app/utils/tooltips.ts with centralized tooltip definitions
• Added helper functions for cache name and forward reason tooltips
• Modified CacheAnalysis.vue to add title attributes to all data fields
• Maintained existing hover functionality while adding educational tooltips

🧪 Testing

• Added comprehensive unit tests for tooltip utilities (15 new tests)
• All existing tests continue to pass (113/113 ✅)
• TypeScript compilation clean with no errors
• ESLint passes with no warnings

📸 Demo

The tooltips make the cache inspector much more educational and user-friendly by providing immediate access to technical definitions and relevant documentation.

Fixes #81.

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