Context

Related to #2336 (Metrics for downloads) and #2561 (Pagination and ordering). The current metrics page displays views over time as a table, but a visual chart would make trends more immediately apparent.

Problem

Tabular data is useful for precise numbers but makes it difficult to:

• Quickly identify trends (growth, decline, seasonality)
• Spot anomalies or spikes in activity
• Compare relative activity across time periods

Proposed Approach

Chart Implementation

• Add a line chart or bar chart above the views over time table
• Use a lightweight JavaScript charting library that's already in use or minimal to add
• Show monthly unique viewers over time with appropriate axis labels

Library Options (in order of preference)

1. Chart.js: Popular, lightweight (~60KB), good documentation, MIT licensed
2. ApexCharts: Modern, responsive, good for time series
3. Native SVG: No dependency but more development effort

Implementation Details

• Pass the views_over_time data to the template as JSON for the chart
• Chart should be responsive and work on mobile
• Include hover tooltips showing exact values
• Consider showing a subset of data (e.g., last 24 months) with option to see more

Alternatives Considered

1. Server-side rendered chart (matplotlib/pillow): Generates image on server, no JS needed, but less interactive and adds server load
2. Sparkline only: Minimal visualization without full chart - simpler but less informative
3. External analytics integration: Link to Google Analytics or similar - requires separate setup and may not have the specific metrics we track

Acceptance Criteria

• Line or bar chart displays views over time
• Chart is responsive and works on mobile devices
• Hover/touch shows exact values for each data point
• Chart handles edge cases (no data, single data point, etc.)
• Minimal impact on page load time