feat: add tooltip support for exact X & Y values on hover

[Winter-Soren]

Add Tooltips to All Dashboard Graphs

Description

This PR adds hover tooltips to all graphs in the Spark Dashboard to show exact values when users hover over data points. This enhancement improves the dashboard's usability by allowing users to see precise values without having to estimate from the axes.

Changes Made

Added tooltips with formatted values to:

1. Line Graphs (Overall Spark RSR)

   • Shows exact date (MMM DD, YYYY format)
   • Shows precise success rate percentage (2 decimal places)
   • Indicates type (HTTP or Graphsync / HTTP only)

2. Histograms (Spark Miner RSR)

   • Shows range of each bin
   • Displays count of miners in each bin
   • Shows type of measurement

3. Time To First Byte (TTFB) Graph

   • Shows formatted date
   • Displays precise TTFB in milliseconds (2 decimal places)

4. Retrieval Result Codes Graph

   • Shows formatted date
   • Displays percentage for each code type
   • Shows code category

5. RSR Buckets Over Time Graphs

   • Shows formatted date
   • Displays exact count of Storage Providers
   • Shows threshold or type information

Implementation Details

• Used Observable Plot's native tooltip system for optimal performance
• Implemented consistent date formatting across all graphs
• Added proper handling for null/undefined values (showing "N/A")
• Maintained color coding and type information in tooltips where relevant

Screenshots

Fixes #11

[Winter-Soren]

Hi @juliangruber, @bajtos, and @NikolasHaimerl, I’ve made some changes to address this issue. I’d really appreciate it if you could review them and share any feedback. Please let me know if I’m on the right track or if any improvements are needed.

[bajtos]

I love this, thank you @Winter-Soren so much for this contribution!

[juliangruber]

In this one, type is listed twice. Can we only show one?

[juliangruber]

Thank you so much, @Winter-Soren!!

[juliangruber]

See comments above

[Winter-Soren]

@juliangruber Thanks a lot for the feedback, Ill rectify and commit!

[juliangruber]

ping @Winter-Soren 🙏

[juliangruber]

I'm going to go ahead with merging this as it's a lot more useful than what we have one. We can fix the kinks later

#31 (comment)