feat(pygal): implement area-basic (#1395)

## Implementation: `area-basic` - pygal

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

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

---
:robot: *[impl-generate
workflow](https://github.com/MarkusNeusinger/pyplots/actions/runs/20447989472)*

---------

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/area-basic/implementations/pygal.py

@@ -1,7 +1,7 @@
 """ pyplots.ai
 area-basic: Basic Area Chart
 Library: pygal 3.1.0 | Python 3.13.11
-Quality: 91/100 | Created: 2025-12-14
+Quality: 91/100 | Created: 2025-12-23
 """
 
 import pygal

plots/area-basic/metadata/pygal.yaml

@@ -1,17 +1,27 @@
 library: pygal
 specification_id: area-basic
-created: 2025-12-14 09:24:22+00:00
-updated: 2025-12-14 09:24:22+00:00
+created: '2025-12-23T00:48:44Z'
+updated: '2025-12-23T01:22:10Z'
 generated_by: claude-opus-4-5-20251101
-workflow_run: 20205863788
-issue: 711
+workflow_run: 20447989472
+issue: 0
 python_version: 3.13.11
 library_version: 3.1.0
 preview_url: https://storage.googleapis.com/pyplots-images/plots/area-basic/pygal/plot.png
 preview_thumb: https://storage.googleapis.com/pyplots-images/plots/area-basic/pygal/plot_thumb.png
 preview_html: https://storage.googleapis.com/pyplots-images/plots/area-basic/pygal/plot.html
 quality_score: 91
 review:
-  strengths: []
-  weaknesses: []
-  improvements: []
+  strengths:
+  - Excellent implementation of the area chart concept with proper fill transparency
+    (0.4 opacity)
+  - Clean, well-structured code following KISS principles
+  - Realistic website traffic data with clear weekly patterns (weekend dips, weekday
+    peaks)
+  - Smart X-axis label strategy showing only every 5th day to prevent clutter
+  - Correct title format and proper canvas sizing (4800x2700)
+  - Good use of pygal Style class for consistent theming
+  weaknesses:
+  - Y-axis label Visitors could include units (e.g., Visitors count)
+  - Data dots could be slightly larger for better visibility at the target resolution
+  - Could leverage more pygal-specific features like custom tooltips or value formatting