feat(plotnine): implement bar-diverging (#6031)

## Implementation: `bar-diverging` - python/plotnine

Implements the **python/plotnine** version of `bar-diverging`.

**File:** `plots/bar-diverging/implementations/python/plotnine.py`

**Parent Issue:** #2009

---
:robot: *[impl-generate
workflow](https://github.com/MarkusNeusinger/anyplot/actions/runs/25546578830)*

---------

Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>
Co-authored-by: Markus Neusinger <2921697+MarkusNeusinger@users.noreply.github.com>

Author: github-actions[bot]

plots/bar-diverging/implementations/python/plotnine.py

@@ -1,27 +1,46 @@
-""" pyplots.ai
+""" anyplot.ai
 bar-diverging: Diverging Bar Chart
-Library: plotnine 0.15.2 | Python 3.13.11
-Quality: 94/100 | Created: 2025-12-25
+Library: plotnine 0.15.4 | Python 3.13.13
+Quality: 91/100 | Updated: 2026-05-08
 """
 
+import importlib.util
+import os
+import sys
+
 import pandas as pd
-from plotnine import (
-    aes,
-    coord_flip,
-    element_line,
-    element_text,
-    geom_bar,
-    geom_hline,
-    ggplot,
-    labs,
-    scale_fill_manual,
-    theme,
-    theme_minimal,
-)
 
 
+# Handle import conflicts: remove current dir and cache
+sys.path = [p for p in sys.path if not p.endswith("python")]
+if "plotnine" in sys.modules:
+    del sys.modules["plotnine"]
+
+# Import plotnine explicitly from site-packages
+plotnine_spec = importlib.util.find_spec("plotnine")
+plotnine = importlib.util.module_from_spec(plotnine_spec)
+sys.modules["plotnine"] = plotnine
+plotnine_spec.loader.exec_module(plotnine)
+
+aes = plotnine.aes
+coord_flip = plotnine.coord_flip
+element_line = plotnine.element_line
+element_rect = plotnine.element_rect
+element_text = plotnine.element_text
+geom_bar = plotnine.geom_bar
+geom_hline = plotnine.geom_hline
+ggplot = plotnine.ggplot
+labs = plotnine.labs
+scale_fill_manual = plotnine.scale_fill_manual
+theme = plotnine.theme
+theme_minimal = plotnine.theme_minimal
+
+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"
+
 # Data - Customer satisfaction survey across product categories
-# Net satisfaction score: % satisfied - % dissatisfied (range -100 to +100)
 categories = [
     "Mobile App",
     "Customer Service",
@@ -47,36 +66,37 @@
 # Create ordered categorical for proper sorting in plot
 df["category"] = pd.Categorical(df["category"], categories=df["category"], ordered=True)
 
-# Color based on positive/negative
+# Color based on positive/negative (Okabe-Ito palette)
 df["sentiment"] = df["value"].apply(lambda x: "Positive" if x >= 0 else "Negative")
 
 # Plot
 plot = (
     ggplot(df, aes(x="category", y="value", fill="sentiment"))
     + geom_bar(stat="identity", width=0.7)
-    + geom_hline(yintercept=0, color="#333333", size=0.8)
+    + geom_hline(yintercept=0, color=INK_SOFT, size=0.8)
     + coord_flip()
-    + scale_fill_manual(values={"Positive": "#306998", "Negative": "#E74C3C"})
+    + scale_fill_manual(values={"Positive": "#009E73", "Negative": "#D55E00"})
     + labs(
         x="Product Category",
         y="Net Satisfaction Score (%)",
-        title="bar-diverging · plotnine · pyplots.ai",
+        title="bar-diverging · plotnine · anyplot.ai",
         fill="Sentiment",
     )
     + theme_minimal()
     + theme(
+        plot_background=element_rect(fill=PAGE_BG, color=PAGE_BG),
+        panel_background=element_rect(fill=PAGE_BG),
+        panel_grid_major_y=element_line(color=INK, size=0.3, alpha=0.10),
+        panel_grid_minor=element_line(color=INK, size=0.2, alpha=0.05),
+        axis_title=element_text(color=INK, size=20),
+        axis_text=element_text(color=INK_SOFT, size=16),
+        plot_title=element_text(color=INK, size=24),
+        legend_background=element_rect(fill=PAGE_BG, color=INK_SOFT),
+        legend_text=element_text(color=INK_SOFT, size=16),
+        legend_title=element_text(color=INK, size=18),
         figure_size=(16, 9),
-        text=element_text(size=14),
-        axis_title=element_text(size=20),
-        axis_text=element_text(size=16),
-        plot_title=element_text(size=24, ha="center"),
-        legend_text=element_text(size=16),
-        legend_title=element_text(size=18),
-        legend_position="right",
-        panel_grid_major_y=element_line(alpha=0.3),
-        panel_grid_minor=element_line(alpha=0),
     )
 )
 
 # Save
-plot.save("plot.png", dpi=300, verbose=False)
+plot.save(f"plot-{THEME}.png", dpi=300, verbose=False)