feat(bokeh): implement stem-basic (#5632)

## Implementation: `stem-basic` - python/bokeh

Implements the **python/bokeh** version of `stem-basic`.

**File:** `plots/stem-basic/implementations/python/bokeh.py`

**Parent Issue:** #972

---
:robot: *[impl-generate
workflow](https://github.com/MarkusNeusinger/anyplot/actions/runs/25172053900)*

---------

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/stem-basic/implementations/python/bokeh.py

@@ -1,22 +1,35 @@
-""" pyplots.ai
+""" anyplot.ai
 stem-basic: Basic Stem Plot
-Library: bokeh 3.8.1 | Python 3.13.11
-Quality: 91/100 | Created: 2025-12-23
+Library: bokeh 3.9.0 | Python 3.13.13
+Quality: 84/100 | Updated: 2026-04-30
 """
 
+import os
+import sys
+
+
+sys.path = [p for p in sys.path if not p.endswith("/python")]
+
 import numpy as np
 from bokeh.io import export_png, output_file, save
 from bokeh.models import ColumnDataSource
 from bokeh.plotting import figure
 
 
+# Theme tokens
+THEME = os.getenv("ANYPLOT_THEME", "light")
+PAGE_BG = "#FAF8F1" if THEME == "light" else "#1A1A17"
+ELEVATED_BG = "#FFFDF6" if THEME == "light" else "#242420"
+INK = "#1A1A17" if THEME == "light" else "#F0EFE8"
+INK_SOFT = "#4A4A44" if THEME == "light" else "#B8B7B0"
+BRAND = "#009E73"
+
 # Data - Discrete signal samples (damped oscillation)
 np.random.seed(42)
 n_points = 30
 x = np.arange(n_points)
 y = np.exp(-0.1 * x) * np.sin(0.5 * x) * 2 + np.random.randn(n_points) * 0.1
 
-# Baseline for stems
 baseline = 0
 
 # Create data sources
@@ -27,39 +40,48 @@
 p = figure(
     width=4800,
     height=2700,
-    title="stem-basic · bokeh · pyplots.ai",
+    title="stem-basic · bokeh · anyplot.ai",
     x_axis_label="Sample Index",
     y_axis_label="Amplitude",
 )
 
 # Draw stems (vertical lines from baseline to data points)
-p.segment(x0="x0", y0="y0", x1="x1", y1="y1", source=stem_source, line_width=4, color="#306998", alpha=0.8)
+p.segment(x0="x0", y0="y0", x1="x1", y1="y1", source=stem_source, line_width=4, color=BRAND, alpha=0.85)
 
 # Draw markers at data points
-p.scatter(x="x", y="y", source=source, size=25, color="#306998", alpha=0.9)
+p.scatter(x="x", y="y", source=source, size=25, color=BRAND, alpha=1.0)
 
 # Draw baseline
-p.line(
-    x=[x.min() - 0.5, x.max() + 0.5],
-    y=[baseline, baseline],
-    line_width=3,
-    line_dash="dashed",
-    color="#999999",
-    alpha=0.6,
-)
+p.line(x=[x.min() - 0.5, x.max() + 0.5], y=[baseline, baseline], line_width=3, color=INK_SOFT, alpha=0.6)
 
-# Styling for 4800x2700
+# Sizing
 p.title.text_font_size = "36pt"
 p.xaxis.axis_label_text_font_size = "28pt"
 p.yaxis.axis_label_text_font_size = "28pt"
 p.xaxis.major_label_text_font_size = "22pt"
 p.yaxis.major_label_text_font_size = "22pt"
 
-# Grid styling
-p.grid.grid_line_alpha = 0.3
-p.grid.grid_line_dash = "dashed"
+# Theme-adaptive chrome
+p.background_fill_color = PAGE_BG
+p.border_fill_color = PAGE_BG
+p.outline_line_color = INK_SOFT
+
+p.title.text_color = INK
+p.xaxis.axis_label_text_color = INK
+p.yaxis.axis_label_text_color = INK
+p.xaxis.major_label_text_color = INK_SOFT
+p.yaxis.major_label_text_color = INK_SOFT
+p.xaxis.axis_line_color = INK_SOFT
+p.yaxis.axis_line_color = INK_SOFT
+p.xaxis.major_tick_line_color = INK_SOFT
+p.yaxis.major_tick_line_color = INK_SOFT
+
+p.xgrid.grid_line_color = INK
+p.ygrid.grid_line_color = INK
+p.xgrid.grid_line_alpha = 0.10
+p.ygrid.grid_line_alpha = 0.10
 
 # Save outputs
-export_png(p, filename="plot.png")
-output_file("plot.html")
+export_png(p, filename=f"plot-{THEME}.png")
+output_file(f"plot-{THEME}.html")
 save(p)