feat(charts): visualize commits over time

[marcgc21]

Description

Create a chart to display the number of commits over time. This will help monitor the project's development pace and identify trends in activity.

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📊 Chart Type

• Line chart or bar chart
• Weekly granularity (preferred)
• Optionally include multiple lines to show per-contributor activity

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🧾 Data Requirements

• Source: GitHub API (GET /repos/:owner/:repo/commits) or local Git logs
• Fields needed:
  • Commit date
  • Commit author (optional)

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✅ Tasks

• Fetch or export commit data grouped by week
• Count commits per week
• (Optional) Separate counts by contributor
• Implement chart using a visualization library (e.g., Chart.js, D3.js, Matplotlib)
• Add legend, axis labels, and chart title
• Handle weeks with zero commits gracefully

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✅ Acceptance Criteria

• Contributors are ordered by activity (highest to lowest)
• Labels and legend are clear and readable
• Chart renders correctly and is exportable or embeddable
• Handles many contributors gracefully (e.g., top 10 only)