feat(plotnine): implement scatter-basic (#5311)

## Implementation: `scatter-basic` - python/plotnine

Implements the **python/plotnine** version of `scatter-basic`.

**File:** `plots/scatter-basic/implementations/python/plotnine.py`

**Parent Issue:** #611

---
:robot: *[impl-generate
workflow](https://github.com/MarkusNeusinger/anyplot/actions/runs/24853804820)*

---------

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/scatter-basic/implementations/python/plotnine.py

@@ -1,71 +1,66 @@
-""" pyplots.ai
+""" anyplot.ai
 scatter-basic: Basic Scatter Plot
-Library: plotnine 0.15.3 | Python 3.14
-Quality: 93/100 | Created: 2025-12-22
+Library: plotnine 0.15.3 | Python 3.14.4
+Quality: 87/100 | Created: 2026-04-23
 """
 
+import os
+
 import numpy as np
 import pandas as pd
 from plotnine import (
     aes,
-    annotate,
     element_blank,
     element_line,
     element_rect,
     element_text,
     geom_point,
     ggplot,
     labs,
-    scale_x_continuous,
-    scale_y_continuous,
-    stat_smooth,
     theme,
     theme_minimal,
 )
 
 
-# Data: Study hours vs exam scores (realistic educational context)
+# Theme tokens
+THEME = os.getenv("ANYPLOT_THEME", "light")
+PAGE_BG = "#FAF8F1" if THEME == "light" else "#1A1A17"
+INK = "#1A1A17" if THEME == "light" else "#F0EFE8"
+INK_SOFT = "#4A4A44" if THEME == "light" else "#B8B7B0"
+GRID = INK
+GRID_ALPHA = 0.10
+BRAND = "#009E73"
+
+# Data
 np.random.seed(42)
-n_points = 150
+n_points = 180
 study_hours = np.random.uniform(1, 10, n_points)
-base_scores = 35 + study_hours * 6
+base_scores = 32 + study_hours * 6
 noise = np.random.randn(n_points) * 7
 exam_scores = np.clip(base_scores + noise, 15, 100)
-
 df = pd.DataFrame({"study_hours": study_hours, "exam_scores": exam_scores})
 
-# Compute correlation for annotation
-correlation = df["study_hours"].corr(df["exam_scores"])
-
 # Plot
 plot = (
     ggplot(df, aes(x="study_hours", y="exam_scores"))
-    + geom_point(fill="#306998", color="#1a3a5c", shape="o", alpha=0.65, size=5, stroke=0.3)
-    + stat_smooth(method="lm", color="#e3822a", size=1.2, alpha=0.15, linetype="solid")
-    + annotate("text", x=2.0, y=97, label=f"r = {correlation:.2f}", size=14, color="#444444", fontstyle="italic")
-    + annotate("text", x=2.0, y=92, label="Strong positive correlation", size=10, color="#777777")
-    + scale_x_continuous(breaks=range(1, 11), limits=(0.5, 10.5))
-    + scale_y_continuous(breaks=range(20, 101, 10), limits=(10, 105))
-    + labs(
-        x="Study Hours (per week)",
-        y="Exam Score (points)",
-        title="scatter-basic · plotnine · pyplots.ai",
-        subtitle="More study time correlates with higher exam performance",
-    )
+    + geom_point(color=BRAND, fill=BRAND, alpha=0.70, size=4.0, stroke=0.4)
+    + labs(x="Study Hours (per week)", y="Exam Score (points)", title="scatter-basic · plotnine · anyplot.ai")
     + theme_minimal()
     + theme(
         figure_size=(16, 9),
-        text=element_text(size=14, color="#333333"),
-        axis_title=element_text(size=20, weight="bold", color="#222222"),
-        axis_text=element_text(size=16, color="#555555"),
-        plot_title=element_text(size=24, weight="bold", color="#1a1a1a"),
-        plot_subtitle=element_text(size=17, color="#666666"),
-        panel_grid_major=element_line(color="#e0e0e0", size=0.4),
+        text=element_text(size=14, color=INK_SOFT),
+        plot_title=element_text(size=24, color=INK, ha="left", margin={"b": 16}),
+        axis_title_x=element_text(size=20, color=INK, margin={"t": 12}),
+        axis_title_y=element_text(size=20, color=INK, margin={"r": 12}),
+        axis_text=element_text(size=16, color=INK_SOFT),
+        axis_ticks=element_blank(),
+        axis_line=element_line(color=INK_SOFT, size=0.6),
+        panel_grid_major=element_line(color=GRID, size=0.4, alpha=GRID_ALPHA),
         panel_grid_minor=element_blank(),
-        plot_background=element_rect(fill="white", color="white"),
-        panel_background=element_rect(fill="#fafafa", color="white"),
+        plot_background=element_rect(fill=PAGE_BG, color=PAGE_BG),
+        panel_background=element_rect(fill=PAGE_BG, color=PAGE_BG),
     )
 )
 
 # Save
-plot.save("plot.png", dpi=300, verbose=False)
+plot.save(f"plot-{THEME}.png", dpi=300, verbose=False)