feat(plotly): implement polar-line (#2754)

## Implementation: `polar-line` - plotly

Implements the **plotly** version of `polar-line`.

**File:** `plots/polar-line/implementations/plotly.py`

---
:robot: *[impl-generate
workflow](https://github.com/MarkusNeusinger/pyplots/actions/runs/20601054802)*

---------

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

Author: github-actions[bot]

plots/polar-line/implementations/plotly.py

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+""" pyplots.ai
+polar-line: Polar Line Plot
+Library: plotly 6.5.0 | Python 3.13.11
+Quality: 94/100 | Created: 2025-12-30
+"""
+
+import numpy as np
+import plotly.graph_objects as go
+
+
+# Data - Average hourly temperature pattern (two seasons)
+np.random.seed(42)
+hours = np.arange(0, 360, 15)  # 24 hours mapped to 360 degrees (15 deg = 1 hour)
+hour_labels = [f"{h}:00" for h in range(24)]
+
+# Summer pattern: warmer during day (12-18h), cooler at night
+summer_base = 22 + 8 * np.sin(np.radians(hours - 90))  # Peak at 180 deg (noon)
+summer_temp = summer_base + np.random.normal(0, 0.5, len(hours))
+
+# Winter pattern: colder overall, less variation
+winter_base = 5 + 5 * np.sin(np.radians(hours - 90))  # Peak at 180 deg (noon)
+winter_temp = winter_base + np.random.normal(0, 0.3, len(hours))
+
+# Close the loop by appending the first value
+hours_closed = np.append(hours, hours[0])
+summer_closed = np.append(summer_temp, summer_temp[0])
+winter_closed = np.append(winter_temp, winter_temp[0])
+
+# Create figure
+fig = go.Figure()
+
+# Summer line
+fig.add_trace(
+    go.Scatterpolar(
+        r=summer_closed,
+        theta=hours_closed,
+        mode="lines+markers",
+        name="Summer",
+        line=dict(color="#FFD43B", width=4),
+        marker=dict(size=10, color="#FFD43B"),
+        hovertemplate="Hour: %{theta}°<br>Temp: %{r:.1f}°C<extra>Summer</extra>",
+    )
+)
+
+# Winter line
+fig.add_trace(
+    go.Scatterpolar(
+        r=winter_closed,
+        theta=hours_closed,
+        mode="lines+markers",
+        name="Winter",
+        line=dict(color="#306998", width=4),
+        marker=dict(size=10, color="#306998"),
+        hovertemplate="Hour: %{theta}°<br>Temp: %{r:.1f}°C<extra>Winter</extra>",
+    )
+)
+
+# Layout
+fig.update_layout(
+    title=dict(
+        text="Hourly Temperature Pattern · polar-line · plotly · pyplots.ai",
+        font=dict(size=28),
+        x=0.5,
+        xanchor="center",
+    ),
+    polar=dict(
+        radialaxis=dict(
+            visible=True,
+            range=[0, 35],
+            tickfont=dict(size=18),
+            title=dict(text="Temperature (°C)", font=dict(size=20)),
+            gridcolor="rgba(0,0,0,0.2)",
+            ticksuffix="°C",
+        ),
+        angularaxis=dict(
+            tickfont=dict(size=16),
+            direction="clockwise",
+            rotation=90,  # Start from top (midnight)
+            tickmode="array",
+            tickvals=list(range(0, 360, 15)),
+            ticktext=hour_labels,
+            gridcolor="rgba(0,0,0,0.2)",
+        ),
+        bgcolor="rgba(255,255,255,0.9)",
+    ),
+    legend=dict(
+        font=dict(size=20), x=1.05, y=0.5, bgcolor="rgba(255,255,255,0.8)", bordercolor="rgba(0,0,0,0.3)", borderwidth=1
+    ),
+    template="plotly_white",
+    margin=dict(l=80, r=150, t=100, b=80),
+)
+
+# Save outputs
+fig.write_image("plot.png", width=1600, height=900, scale=3)
+fig.write_html("plot.html", include_plotlyjs="cdn")

plots/polar-line/metadata/plotly.yaml

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+library: plotly
+specification_id: polar-line
+created: '2025-12-30T16:30:10Z'
+updated: '2025-12-30T16:38:46Z'
+generated_by: claude-opus-4-5-20251101
+workflow_run: 20601054802
+issue: 0
+python_version: 3.13.11
+library_version: 6.5.0
+preview_url: https://storage.googleapis.com/pyplots-images/plots/polar-line/plotly/plot.png
+preview_thumb: https://storage.googleapis.com/pyplots-images/plots/polar-line/plotly/plot_thumb.png
+preview_html: https://storage.googleapis.com/pyplots-images/plots/polar-line/plotly/plot.html
+quality_score: 94
+review:
+  strengths:
+  - 'Excellent data choice: hourly temperature pattern is a perfect real-world use
+    case for polar plots, demonstrating cyclical data visualization'
+  - 'Proper loop closure: appending first value to close the polar shape is correctly
+    implemented'
+  - 'Good visual contrast: yellow vs dark blue colors are highly distinguishable and
+    colorblind-safe'
+  - 'Appropriate sizing: line width=4 and marker size=10 are well-suited for the data
+    density'
+  - Custom hover templates enhance interactivity
+  weaknesses:
+  - The radial axis has both a title Temperature (°C) and ticksuffix=°C, creating
+    slight redundancy in the center area
+  - Could leverage more Plotly-specific features like fill=toself for area between
+    lines or animation frames