feat(bokeh): implement icicle-basic (#2536)

## Implementation: `icicle-basic` - bokeh

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

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

---
:robot: *[impl-generate
workflow](https://github.com/MarkusNeusinger/pyplots/actions/runs/20585400055)*

---------

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Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

Author: github-actions[bot]

plots/icicle-basic/implementations/bokeh.py

@@ -0,0 +1,197 @@
+""" pyplots.ai
+icicle-basic: Basic Icicle Chart
+Library: bokeh 3.8.1 | Python 3.13.11
+Quality: 92/100 | Created: 2025-12-30
+"""
+
+from bokeh.io import export_png, output_file, save
+from bokeh.models import ColumnDataSource, Label
+from bokeh.plotting import figure
+
+
+# Data - File system hierarchy with nested folders and file sizes
+nodes = [
+    {"name": "Root", "parent": None, "value": 0},
+    {"name": "Documents", "parent": "Root", "value": 0},
+    {"name": "Media", "parent": "Root", "value": 0},
+    {"name": "Code", "parent": "Root", "value": 0},
+    {"name": "Reports", "parent": "Documents", "value": 350},
+    {"name": "Contracts", "parent": "Documents", "value": 250},
+    {"name": "Notes", "parent": "Documents", "value": 150},
+    {"name": "Images", "parent": "Media", "value": 500},
+    {"name": "Videos", "parent": "Media", "value": 800},
+    {"name": "Audio", "parent": "Media", "value": 300},
+    {"name": "Python", "parent": "Code", "value": 400},
+    {"name": "JavaScript", "parent": "Code", "value": 350},
+    {"name": "Data", "parent": "Code", "value": 200},
+]
+
+# Build tree structure
+node_dict = {n["name"]: n for n in nodes}
+children = {n["name"]: [] for n in nodes}
+for n in nodes:
+    if n["parent"]:
+        children[n["parent"]].append(n["name"])
+
+
+# Calculate leaf values for parent nodes (sum of children)
+def calc_value(name):
+    if children[name]:
+        return sum(calc_value(c) for c in children[name])
+    return node_dict[name]["value"]
+
+
+for n in nodes:
+    n["computed_value"] = calc_value(n["name"])
+
+
+# Assign levels (depth in tree)
+def assign_level(name, level):
+    node_dict[name]["level"] = level
+    for c in children[name]:
+        assign_level(c, level + 1)
+
+
+assign_level("Root", 0)
+max_level = max(n["level"] for n in nodes)
+
+# Colors by level - Python Blue to Yellow gradient
+level_colors = ["#306998", "#4A7DAA", "#6591BC", "#FFD43B"]
+
+
+# Calculate positions for icicle layout (horizontal, top-down)
+# Each level is a row, width proportional to value
+def layout_icicle(name, x_start, x_end, rects):
+    node = node_dict[name]
+    level = node["level"]
+
+    # Rectangle for this node
+    rect = {
+        "name": name,
+        "level": level,
+        "x_start": x_start,
+        "x_end": x_end,
+        "y_start": max_level - level,
+        "y_end": max_level - level + 1,
+        "value": node["computed_value"],
+        "color": level_colors[min(level, len(level_colors) - 1)],
+    }
+    rects.append(rect)
+
+    # Layout children
+    if children[name]:
+        total_child_value = sum(node_dict[c]["computed_value"] for c in children[name])
+        current_x = x_start
+        for c in children[name]:
+            child_value = node_dict[c]["computed_value"]
+            child_width = (x_end - x_start) * (child_value / total_child_value)
+            layout_icicle(c, current_x, current_x + child_width, rects)
+            current_x += child_width
+
+
+rects = []
+layout_icicle("Root", 0, 100, rects)
+
+# Prepare data for Bokeh
+x_centers = [(r["x_start"] + r["x_end"]) / 2 for r in rects]
+y_centers = [(r["y_start"] + r["y_end"]) / 2 for r in rects]
+widths = [r["x_end"] - r["x_start"] for r in rects]
+heights = [0.95 for r in rects]  # Slight gap between levels
+colors = [r["color"] for r in rects]
+names = [r["name"] for r in rects]
+values = [r["value"] for r in rects]
+
+source = ColumnDataSource(
+    data={
+        "x": x_centers,
+        "y": y_centers,
+        "width": widths,
+        "height": heights,
+        "color": colors,
+        "name": names,
+        "value": values,
+    }
+)
+
+# Create figure
+p = figure(
+    width=4800,
+    height=2700,
+    title="File System Structure · icicle-basic · bokeh · pyplots.ai",
+    x_range=(-12, 102),
+    y_range=(-0.3, max_level + 0.8),
+    tools="",
+    toolbar_location=None,
+)
+
+# Draw rectangles
+p.rect(
+    x="x",
+    y="y",
+    width="width",
+    height="height",
+    source=source,
+    fill_color="color",
+    line_color="white",
+    line_width=3,
+    fill_alpha=0.9,
+)
+
+# Add labels for rectangles with sufficient width
+for r in rects:
+    rect_width = r["x_end"] - r["x_start"]
+    x_center = (r["x_start"] + r["x_end"]) / 2
+    y_center = (r["y_start"] + r["y_end"]) / 2
+
+    # Only label if rectangle is wide enough
+    if rect_width > 4:
+        font_size = "24pt" if rect_width > 20 else ("20pt" if rect_width > 10 else "16pt")
+        label_text = r["name"]
+        if r["level"] > 0 and rect_width > 6:
+            label_text = f"{r['name']} ({r['value']} MB)"
+
+        label = Label(
+            x=x_center,
+            y=y_center,
+            text=label_text,
+            text_align="center",
+            text_baseline="middle",
+            text_font_size=font_size,
+            text_color="white" if r["level"] < 3 else "#1a1a1a",
+        )
+        p.add_layout(label)
+
+# Styling
+p.title.text_font_size = "36pt"
+p.title.align = "center"
+
+# Hide axes for cleaner look
+p.xaxis.visible = False
+p.yaxis.visible = False
+p.xgrid.visible = False
+p.ygrid.visible = False
+
+# Remove outline
+p.outline_line_color = None
+
+# Background
+p.background_fill_color = "#fafafa"
+
+# Add level labels on the left
+level_labels = ["Root", "Categories", "Subcategories"]
+for i, label_text in enumerate(level_labels[: max_level + 1]):
+    label = Label(
+        x=-1,
+        y=max_level - i + 0.5,
+        text=label_text,
+        text_align="right",
+        text_baseline="middle",
+        text_font_size="20pt",
+        text_color="#666666",
+    )
+    p.add_layout(label)
+
+# Save as PNG and HTML
+export_png(p, filename="plot.png")
+output_file("plot.html", title="icicle-basic · bokeh · pyplots.ai")
+save(p)

plots/icicle-basic/metadata/bokeh.yaml

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+library: bokeh
+specification_id: icicle-basic
+created: '2025-12-30T00:06:12Z'
+updated: '2025-12-30T00:09:11Z'
+generated_by: claude-opus-4-5-20251101
+workflow_run: 20585400055
+issue: 0
+python_version: 3.13.11
+library_version: 3.8.1
+preview_url: https://storage.googleapis.com/pyplots-images/plots/icicle-basic/bokeh/plot.png
+preview_thumb: https://storage.googleapis.com/pyplots-images/plots/icicle-basic/bokeh/plot_thumb.png
+preview_html: https://storage.googleapis.com/pyplots-images/plots/icicle-basic/bokeh/plot.html
+quality_score: 92
+review:
+  strengths:
+  - Excellent hierarchical visualization with clear parent-child relationships through
+    spatial adjacency
+  - Smart conditional labeling that hides text for small rectangles and includes values
+    for larger ones
+  - Beautiful color gradient by hierarchy level (Python Blue theme)
+  - Level labels on the left margin provide clear context for each row
+  - Proportional sizing accurately represents values across the hierarchy
+  - Clean white borders and light background enhance readability
+  weaknesses:
+  - Code uses helper functions (calc_value, assign_level, layout_icicle) instead of
+    KISS linear script style
+  - Could leverage Bokeh HoverTool for interactive tooltips showing node details