spec: add line-interactive specification (#2788)

## New Specification: `line-interactive`

Related to #2787

---

### specification.md

# line-interactive: Interactive Line Chart with Hover and Zoom

## Description

An interactive line chart that enables detailed data exploration through
hover tooltips, zoom/pan functionality, and range selection. Unlike
static line charts, this visualization allows users to examine exact
values on hover, zoom into areas of interest, and select time ranges for
focused analysis. It excels at making large time series accessible and
revealing fine-grained patterns that would be lost in static views.

## Applications

- Exploring financial data with ability to zoom into specific trading
periods and see exact prices
- Analyzing sensor data or IoT metrics where users need to drill down
into anomalies
- Interactive dashboards for monitoring website traffic with range
selection for period comparison

## Data

- `x` (numeric/datetime) - Sequential or time values representing the
independent variable
- `y` (numeric) - Continuous values representing the measured quantity
- Size: 50-1000+ points (interactivity handles larger datasets well)
- Example: Stock prices over time, hourly server metrics, daily
temperature readings

## Notes

- Hover tooltips should display exact x and y values with appropriate
formatting
- Zoom should support both mouse wheel and click-drag box selection
- Pan functionality for navigating zoomed views
- Range selector or slider for quick navigation of time series
- Reset zoom button to return to full view
- Smooth animations for zoom/pan transitions enhance user experience

---

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plots/line-interactive/specification.md

@@ -0,0 +1,27 @@
+# line-interactive: Interactive Line Chart with Hover and Zoom
+
+## Description
+
+An interactive line chart that enables detailed data exploration through hover tooltips, zoom/pan functionality, and range selection. Unlike static line charts, this visualization allows users to examine exact values on hover, zoom into areas of interest, and select time ranges for focused analysis. It excels at making large time series accessible and revealing fine-grained patterns that would be lost in static views.
+
+## Applications
+
+- Exploring financial data with ability to zoom into specific trading periods and see exact prices
+- Analyzing sensor data or IoT metrics where users need to drill down into anomalies
+- Interactive dashboards for monitoring website traffic with range selection for period comparison
+
+## Data
+
+- `x` (numeric/datetime) - Sequential or time values representing the independent variable
+- `y` (numeric) - Continuous values representing the measured quantity
+- Size: 50-1000+ points (interactivity handles larger datasets well)
+- Example: Stock prices over time, hourly server metrics, daily temperature readings
+
+## Notes
+
+- Hover tooltips should display exact x and y values with appropriate formatting
+- Zoom should support both mouse wheel and click-drag box selection
+- Pan functionality for navigating zoomed views
+- Range selector or slider for quick navigation of time series
+- Reset zoom button to return to full view
+- Smooth animations for zoom/pan transitions enhance user experience

plots/line-interactive/specification.yaml

@@ -0,0 +1,31 @@
+# Specification-level metadata for line-interactive
+# Auto-synced to PostgreSQL on push to main
+
+spec_id: line-interactive
+title: Interactive Line Chart with Hover and Zoom
+
+# Specification tracking
+created: 2025-12-30T17:31:04Z
+updated: 2025-12-30T17:31:04Z
+issue: 2787
+suggested: MarkusNeusinger
+
+# Classification tags (applies to all library implementations)
+# See docs/concepts/tagging-system.md for detailed guidelines
+tags:
+  plot_type:
+    - line
+  data_type:
+    - numeric
+    - timeseries
+    - continuous
+  domain:
+    - general
+    - finance
+    - technology
+  features:
+    - interactive
+    - hover
+    - zoom
+    - pan
+    - range-selection