feat(highcharts): implement sn-curve-basic (#7525)

## Implementation: `sn-curve-basic` - python/highcharts

Implements the **python/highcharts** version of `sn-curve-basic`.

**File:** `plots/sn-curve-basic/implementations/python/highcharts.py`

**Parent Issue:** #3826

---
:robot: *[impl-generate
workflow](https://github.com/MarkusNeusinger/anyplot/actions/runs/26168794164)*

---------

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/sn-curve-basic/implementations/python/highcharts.py

@@ -1,7 +1,7 @@
 """ anyplot.ai
 sn-curve-basic: S-N Curve (Wöhler Curve)
 Library: highcharts unknown | Python 3.13.13
-Quality: 87/100 | Updated: 2026-05-20
+Quality: 89/100 | Updated: 2026-05-20
 """
 
 import os
@@ -15,6 +15,7 @@
 from highcharts_core.options import HighchartsOptions
 from highcharts_core.options.series.area import LineSeries
 from highcharts_core.options.series.scatter import ScatterSeries
+from PIL import Image
 from selenium import webdriver
 from selenium.webdriver.chrome.options import Options
 
@@ -73,10 +74,11 @@
     "height": 1800,
     "backgroundColor": PAGE_BG,
     "style": {"fontFamily": "Arial, sans-serif", "color": INK},
-    "marginBottom": 120,
+    "marginBottom": 140,
     "marginLeft": 150,
     "marginRight": 80,
     "marginTop": 100,
+    "plotBorderWidth": 0,
 }
 
 chart.options.title = {
@@ -92,7 +94,7 @@
         "color": "rgba(213,94,0,0.07)",
         "label": {
             "text": "Low-Cycle Fatigue",
-            "style": {"fontSize": "32px", "color": INK_SOFT},
+            "style": {"fontSize": "36px", "color": INK_SOFT},
             "align": "center",
             "verticalAlign": "top",
             "y": 30,
@@ -104,7 +106,7 @@
         "color": "rgba(0,114,178,0.05)",
         "label": {
             "text": "High-Cycle Fatigue",
-            "style": {"fontSize": "32px", "color": INK_SOFT},
+            "style": {"fontSize": "36px", "color": INK_SOFT},
             "align": "center",
             "verticalAlign": "top",
             "y": 30,
@@ -116,7 +118,7 @@
         "color": "rgba(0,158,115,0.06)",
         "label": {
             "text": "Infinite Life",
-            "style": {"fontSize": "32px", "color": INK_SOFT},
+            "style": {"fontSize": "36px", "color": INK_SOFT},
             "align": "center",
             "verticalAlign": "top",
             "y": 30,
@@ -151,40 +153,40 @@
     "plotLines": [
         {
             "value": ultimate_strength,
-            "color": "#E53935",
+            "color": "#CC79A7",
             "width": 4,
             "dashStyle": "Dash",
             "label": {
                 "text": f"Ultimate Strength ({ultimate_strength} MPa)",
-                "align": "right",
-                "style": {"fontSize": "34px", "color": "#E53935", "fontWeight": "bold"},
-                "x": -10,
+                "align": "left",
+                "style": {"fontSize": "34px", "color": "#CC79A7", "fontWeight": "bold"},
+                "x": 10,
             },
             "zIndex": 3,
         },
         {
             "value": yield_strength,
-            "color": "#FB8C00",
+            "color": "#E69F00",
             "width": 4,
             "dashStyle": "Dash",
             "label": {
                 "text": f"Yield Strength ({yield_strength} MPa)",
-                "align": "right",
-                "style": {"fontSize": "34px", "color": "#FB8C00", "fontWeight": "bold"},
-                "x": -10,
+                "align": "left",
+                "style": {"fontSize": "34px", "color": "#E69F00", "fontWeight": "bold"},
+                "x": 10,
             },
             "zIndex": 3,
         },
         {
             "value": endurance_limit,
-            "color": "#43A047",
+            "color": "#56B4E9",
             "width": 4,
             "dashStyle": "Dash",
             "label": {
                 "text": f"Endurance Limit ({endurance_limit} MPa)",
-                "align": "right",
-                "style": {"fontSize": "34px", "color": "#43A047", "fontWeight": "bold"},
-                "x": -10,
+                "align": "left",
+                "style": {"fontSize": "34px", "color": "#56B4E9", "fontWeight": "bold"},
+                "x": 10,
             },
             "zIndex": 3,
         },
@@ -201,7 +203,7 @@
     "verticalAlign": "top",
     "layout": "vertical",
     "x": -60,
-    "y": 100,
+    "y": 140,
 }
 
 chart.options.plot_options = {
@@ -253,16 +255,28 @@
     temp_path = f.name
 
 chrome_options = Options()
-chrome_options.add_argument("--headless")
+chrome_options.add_argument("--headless=new")
 chrome_options.add_argument("--no-sandbox")
 chrome_options.add_argument("--disable-dev-shm-usage")
 chrome_options.add_argument("--disable-gpu")
+chrome_options.add_argument("--hide-scrollbars")
 chrome_options.add_argument("--window-size=3200,1800")
 
 driver = webdriver.Chrome(options=chrome_options)
+# CDP override makes the viewport authoritative; --window-size alone is eaten by Chrome chrome
+driver.execute_cdp_cmd(
+    "Emulation.setDeviceMetricsOverride", {"width": 3200, "height": 1800, "deviceScaleFactor": 1, "mobile": False}
+)
 driver.get(f"file://{temp_path}")
 time.sleep(5)
 driver.save_screenshot(f"plot-{THEME}.png")
 driver.quit()
 
 Path(temp_path).unlink()
+
+# PIL safety net: pin to exact 3200×1800 in case of ±1-2 px rounding
+_img = Image.open(f"plot-{THEME}.png").convert("RGB")
+if _img.size != (3200, 1800):
+    _norm = Image.new("RGB", (3200, 1800), PAGE_BG)
+    _norm.paste(_img, ((3200 - _img.size[0]) // 2, (1800 - _img.size[1]) // 2))
+    _norm.save(f"plot-{THEME}.png")