feat(bokeh): implement bullet-basic (#1040)

## Implementation: `bullet-basic` - bokeh

Implements the **bokeh** version of `bullet-basic`.

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

**Parent Issue:** #999

---
:robot: *[impl-generate
workflow](https://github.com/MarkusNeusinger/pyplots/actions/runs/20257947614)*

---------

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/bullet-basic/implementations/bokeh.py

@@ -0,0 +1,122 @@
+"""
+bullet-basic: Basic Bullet Chart
+Library: bokeh
+"""
+
+from bokeh.io import export_png, output_file, save
+from bokeh.models import Label
+from bokeh.plotting import figure
+
+
+# Data - Sales performance metrics with targets
+metrics = [
+    {"label": "Revenue", "actual": 275, "target": 250, "ranges": [150, 225, 300]},
+    {"label": "Profit", "actual": 85, "target": 100, "ranges": [50, 75, 100]},
+    {"label": "Orders", "actual": 320, "target": 350, "ranges": [200, 300, 400]},
+    {"label": "Customers", "actual": 1450, "target": 1200, "ranges": [800, 1100, 1500]},
+    {"label": "Satisfaction", "actual": 4.2, "target": 4.5, "ranges": [3.0, 4.0, 5.0]},
+]
+
+# Configuration
+num_metrics = len(metrics)
+bar_spacing = 1.5  # Space between each bullet row
+bar_height = 0.8  # Maximum height of range bars
+
+# Qualitative range colors (grayscale: poor, satisfactory, good - light to dark)
+range_colors = ["#dddddd", "#aaaaaa", "#777777"]
+
+# Create figure
+p = figure(
+    width=4800,
+    height=2700,
+    x_range=(0, 110),
+    y_range=(-0.5, num_metrics * bar_spacing),
+    title="bullet-basic · bokeh · pyplots.ai",
+    x_axis_label="% of Target Range",
+    toolbar_location=None,
+)
+
+# Remove y-axis ticks and gridlines
+p.yaxis.visible = False
+p.ygrid.grid_line_color = None
+p.xgrid.grid_line_alpha = 0.3
+p.xgrid.grid_line_dash = "dashed"
+
+# Draw bullets for each metric
+for i, metric in enumerate(metrics):
+    y_pos = (num_metrics - 1 - i) * bar_spacing  # Reverse so first is at top
+    actual = metric["actual"]
+    target = metric["target"]
+    ranges = metric["ranges"]
+    max_range = ranges[-1]
+
+    # Normalize values to percentage of max range
+    norm_actual = (actual / max_range) * 100
+    norm_target = (target / max_range) * 100
+    norm_ranges = [(r / max_range) * 100 for r in ranges]
+
+    # Draw qualitative ranges (background bands) - from outer to inner
+    for j in range(len(norm_ranges) - 1, -1, -1):
+        range_width = norm_ranges[j]
+        height_factor = 1 - j * 0.25  # Decrease height for inner ranges
+        h = bar_height * height_factor
+        p.rect(x=range_width / 2, y=y_pos, width=range_width, height=h, color=range_colors[j], line_color=None)
+
+    # Draw actual value bar (primary measure)
+    actual_bar_height = bar_height * 0.35
+    p.rect(x=norm_actual / 2, y=y_pos, width=norm_actual, height=actual_bar_height, color="#306998", line_color=None)
+
+    # Draw target marker (thin black vertical line)
+    target_marker_height = bar_height * 0.6
+    p.rect(x=norm_target, y=y_pos, width=0.8, height=target_marker_height, color="#1a1a1a", line_color=None)
+
+    # Add metric label on the left
+    label = Label(
+        x=-2,
+        y=y_pos,
+        text=metric["label"],
+        text_font_size="22pt",
+        text_color="#333333",
+        text_align="right",
+        text_baseline="middle",
+        text_font_style="bold",
+    )
+    p.add_layout(label)
+
+    # Add actual value text label on the right
+    value_label = Label(
+        x=norm_actual + 3,
+        y=y_pos,
+        text=str(metric["actual"]),
+        text_font_size="18pt",
+        text_color="#306998",
+        text_align="left",
+        text_baseline="middle",
+        text_font_style="bold",
+    )
+    p.add_layout(value_label)
+
+# Extend x_range to accommodate labels (but clip axis display)
+p.x_range.start = -35
+p.x_range.end = 115
+
+# Styling
+p.title.text_font_size = "36pt"
+p.title.text_color = "#333333"
+p.title.align = "center"
+p.xaxis.axis_label_text_font_size = "24pt"
+p.xaxis.major_label_text_font_size = "18pt"
+
+# Only show positive tick marks on x-axis
+p.xaxis.ticker = [0, 20, 40, 60, 80, 100]
+
+# Axis styling
+p.xaxis.axis_line_color = "#666666"
+p.outline_line_color = None
+
+# Save as PNG
+export_png(p, filename="plot.png")
+
+# Save as HTML for interactivity
+output_file("plot.html")
+save(p)

plots/bullet-basic/metadata/bokeh.yaml

@@ -0,0 +1,23 @@
+# Per-library metadata for bokeh implementation of bullet-basic
+# Auto-generated by impl-generate.yml
+
+library: bokeh
+specification_id: bullet-basic
+
+# Preview URLs (filled by workflow)
+preview_url: https://storage.googleapis.com/pyplots-images/plots/bullet-basic/bokeh/plot.png
+preview_thumb: https://storage.googleapis.com/pyplots-images/plots/bullet-basic/bokeh/plot_thumb.png
+preview_html: https://storage.googleapis.com/pyplots-images/plots/bullet-basic/bokeh/plot.html
+
+current:
+  version: 0
+  generated_at: 2025-12-16T05:52:35Z
+  generated_by: claude-opus-4-5-20251101
+  workflow_run: 20257947614
+  issue: 999
+  quality_score: 95
+  # Version info (filled by workflow)
+  python_version: "3.13.11"
+  library_version: "unknown"
+
+history: []