feat(pygal): implement line-basic (#1350)

## Implementation: `line-basic` - pygal

Implements the **pygal** version of `line-basic`.

**File:** `plots/line-basic/implementations/pygal.py`

---
:robot: *[impl-generate
workflow](https://github.com/MarkusNeusinger/pyplots/actions/runs/20447579672)*

---------

Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>
Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

Author: github-actions[bot]

plots/line-basic/implementations/pygal.py

@@ -1,14 +1,14 @@
 """ pyplots.ai
 line-basic: Basic Line Plot
 Library: pygal 3.1.0 | Python 3.13.11
-Quality: 92/100 | Created: 2025-12-13
+Quality: 92/100 | Created: 2025-12-23
 """
 
 import pygal
 from pygal.style import Style
 
 
-# Data - Monthly average temperatures
+# Data - Monthly average temperatures (°C) for a temperate climate
 months = ["Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"]
 temperatures = [2.3, 3.5, 7.2, 11.8, 16.4, 19.8, 22.1, 21.5, 17.6, 12.3, 7.1, 3.4]
 
@@ -31,9 +31,9 @@
 chart = pygal.Line(
     width=4800,
     height=2700,
-    title="line-basic \u00b7 pygal \u00b7 pyplots.ai",
+    title="line-basic · pygal · pyplots.ai",
     x_title="Month",
-    y_title="Temperature (\u00b0C)",
+    y_title="Temperature (°C)",
     style=custom_style,
     show_dots=True,
     dots_size=8,

plots/line-basic/metadata/pygal.yaml

@@ -1,17 +1,25 @@
 library: pygal
 specification_id: line-basic
-created: 2025-12-13 23:40:10+00:00
-updated: 2025-12-13 23:40:10+00:00
+created: '2025-12-23T00:24:03Z'
+updated: '2025-12-23T00:28:11Z'
 generated_by: claude-opus-4-5-20251101
-workflow_run: 20199516648
-issue: 653
+workflow_run: 20447579672
+issue: 0
 python_version: 3.13.11
 library_version: 3.1.0
 preview_url: https://storage.googleapis.com/pyplots-images/plots/line-basic/pygal/plot.png
 preview_thumb: https://storage.googleapis.com/pyplots-images/plots/line-basic/pygal/plot_thumb.png
 preview_html: https://storage.googleapis.com/pyplots-images/plots/line-basic/pygal/plot.html
 quality_score: 92
 review:
-  strengths: []
-  weaknesses: []
-  improvements: []
+  strengths:
+  - Clean, minimal design that matches spec requirements perfectly
+  - Excellent use of custom Style for font sizing on large canvas
+  - Realistic temperature data that clearly demonstrates seasonal trends
+  - Proper title format following pyplots.ai conventions
+  - Good color choice with accessible contrast
+  weaknesses:
+  - Legend at bottom-left appears small and somewhat disconnected from the chart
+  - Font sizes in the library rules suggest smaller values (28/18/16) but implementation
+    uses larger (72/48/42) - while this works for the large canvas, it deviates from
+    the template