feat(plotly): implement area-mountain-panorama (#5371)

## Implementation: `area-mountain-panorama` - python/plotly

Implements the **python/plotly** version of `area-mountain-panorama`.

**File:**
`plots/area-mountain-panorama/implementations/python/plotly.py`

**Parent Issue:** #5365

---
:robot: *[impl-generate
workflow](https://github.com/MarkusNeusinger/anyplot/actions/runs/24919062809)*

---------

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/area-mountain-panorama/implementations/python/plotly.py

@@ -0,0 +1,200 @@
+""" anyplot.ai
+area-mountain-panorama: Mountain Panorama Profile with Labeled Peaks
+Library: plotly 6.7.0 | Python 3.14.4
+Quality: 89/100 | Created: 2026-04-25
+"""
+
+import os
+
+import numpy as np
+import plotly.graph_objects as go
+
+
+# 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"
+INK_MUTED = "#6B6A63" if THEME == "light" else "#A8A79F"
+GRID = "rgba(26,26,23,0.10)" if THEME == "light" else "rgba(240,239,232,0.10)"
+BRAND = "#009E73"
+
+# Data — Wallis (Valais) panorama: peaks ordered along a 0–180° angular sweep
+peaks = [
+    ("Weisshorn", 8, 4506),
+    ("Zinalrothorn", 20, 4221),
+    ("Ober Gabelhorn", 31, 4063),
+    ("Dent Blanche", 42, 4358),
+    ("Matterhorn", 58, 4478),
+    ("Breithorn", 72, 4164),
+    ("Pollux", 81, 4092),
+    ("Castor", 89, 4223),
+    ("Liskamm", 97, 4527),
+    ("Dufourspitze", 109, 4634),
+    ("Strahlhorn", 121, 4190),
+    ("Rimpfischhorn", 132, 4199),
+    ("Allalinhorn", 142, 4027),
+    ("Alphubel", 152, 4206),
+    ("Täschhorn", 162, 4491),
+    ("Dom", 174, 4545),
+]
+
+# Build ridgeline control points: peaks alternating with saddles (cols)
+np.random.seed(42)
+ctrl_x = [-3.0]
+ctrl_y = [3250.0]
+for i, (_, ang, el) in enumerate(peaks):
+    ctrl_x.append(float(ang))
+    ctrl_y.append(float(el))
+    if i < len(peaks) - 1:
+        next_ang = peaks[i + 1][1]
+        next_el = peaks[i + 1][2]
+        col_ang = (ang + next_ang) / 2 + np.random.uniform(-1.2, 1.2)
+        col_drop = np.random.uniform(420, 820)
+        col_el = min(el, next_el) - col_drop
+        ctrl_x.append(float(col_ang))
+        ctrl_y.append(float(col_el))
+ctrl_x.append(184.0)
+ctrl_y.append(3350.0)
+
+ctrl_x = np.array(ctrl_x)
+ctrl_y = np.array(ctrl_y)
+
+# Smooth ridgeline via cosine smoothstep between adjacent control points
+ridge_x = []
+ridge_y = []
+for i in range(len(ctrl_x) - 1):
+    n = 80
+    last = i == len(ctrl_x) - 2
+    t = np.linspace(0.0, 1.0, n, endpoint=last)
+    s = 0.5 - 0.5 * np.cos(np.pi * t)
+    ridge_x.append(ctrl_x[i] + (ctrl_x[i + 1] - ctrl_x[i]) * t)
+    ridge_y.append(ctrl_y[i] + (ctrl_y[i + 1] - ctrl_y[i]) * s)
+ridge_x = np.concatenate(ridge_x)
+ridge_y = np.concatenate(ridge_y)
+
+# Anchor the silhouette polygon at the lower edge of the visible y-range
+Y_FLOOR = 2500
+poly_x = np.concatenate([[ridge_x[0]], ridge_x, [ridge_x[-1]]])
+poly_y = np.concatenate([[Y_FLOOR], ridge_y, [Y_FLOOR]])
+
+# Plot
+fig = go.Figure()
+
+# Mountain silhouette (first categorical series — brand green)
+fig.add_trace(
+    go.Scatter(
+        x=poly_x,
+        y=poly_y,
+        mode="lines",
+        line={"color": BRAND, "width": 2},
+        fill="toself",
+        fillcolor=BRAND,
+        hoverinfo="skip",
+        showlegend=False,
+    )
+)
+
+# Leader lines + peak markers + labels
+LEVEL_TIERS = [4880, 5040, 5200]
+annotations = []
+for i, (name, ang, el) in enumerate(peaks):
+    label_y = LEVEL_TIERS[i % 3]
+    is_focal = name == "Matterhorn"
+
+    # Leader line (thin, theme-adaptive)
+    fig.add_trace(
+        go.Scatter(
+            x=[ang, ang],
+            y=[el + 25, label_y - 80],
+            mode="lines",
+            line={"color": INK_SOFT, "width": 1},
+            hoverinfo="skip",
+            showlegend=False,
+        )
+    )
+
+    # Summit dot (slightly larger for the focal peak)
+    fig.add_trace(
+        go.Scatter(
+            x=[ang],
+            y=[el],
+            mode="markers",
+            marker={"size": 10 if is_focal else 6, "color": INK if is_focal else INK_SOFT, "line": {"width": 0}},
+            hoverinfo="skip",
+            showlegend=False,
+        )
+    )
+
+    # Label: name on top, elevation below
+    name_size = 17 if is_focal else 14
+    weight = "700" if is_focal else "600"
+    annotations.append(
+        {
+            "x": ang,
+            "y": label_y,
+            "text": (
+                f"<span style='font-size:{name_size}px;font-weight:{weight};color:{INK}'>{name}</span><br>"
+                f"<span style='font-size:13px;color:{INK_MUTED}'>{el:,} m</span>"
+            ),
+            "showarrow": False,
+            "align": "center",
+            "xanchor": "center",
+            "yanchor": "middle",
+        }
+    )
+
+# Subtitle / footnote
+annotations.append(
+    {
+        "x": 0.5,
+        "y": 1.08,
+        "xref": "paper",
+        "yref": "paper",
+        "text": f"<span style='color:{INK_SOFT}'>Wallis panorama — sixteen 4 000 m peaks of the Pennine Alps</span>",
+        "showarrow": False,
+        "font": {"size": 18},
+        "xanchor": "center",
+    }
+)
+
+fig.update_layout(
+    title={
+        "text": "area-mountain-panorama · plotly · anyplot.ai",
+        "font": {"size": 28, "color": INK},
+        "x": 0.5,
+        "xanchor": "center",
+        "y": 0.96,
+    },
+    annotations=annotations,
+    paper_bgcolor=PAGE_BG,
+    plot_bgcolor=PAGE_BG,
+    font={"color": INK},
+    xaxis={
+        "range": [-3, 184],
+        "showgrid": False,
+        "showticklabels": False,
+        "ticks": "",
+        "zeroline": False,
+        "showline": False,
+        "fixedrange": True,
+    },
+    yaxis={
+        "title": {"text": "Elevation (m)", "font": {"size": 22, "color": INK}},
+        "tickfont": {"size": 18, "color": INK_SOFT},
+        "tickvals": [2500, 3000, 3500, 4000, 4500, 5000],
+        "ticksuffix": "  ",
+        "gridcolor": GRID,
+        "linecolor": INK_SOFT,
+        "showgrid": True,
+        "zeroline": False,
+        "showline": False,
+        "ticks": "",
+        "range": [Y_FLOOR, 5400],
+    },
+    margin={"l": 120, "r": 80, "t": 160, "b": 60},
+)
+
+fig.write_image(f"plot-{THEME}.png", width=1600, height=900, scale=3)
+fig.write_html(f"plot-{THEME}.html", include_plotlyjs="cdn")