feat(matplotlib): implement histogram-basic (#477)

## Summary
Implements `histogram-basic` for **matplotlib** library.

**Parent Issue:** #206
**Sub-Issue:** #323
**Base Branch:** `plot/histogram-basic`
**Attempt:** 1/3

## Implementation
- `plots/matplotlib/hist/histogram-basic/default.py`

## Changes
- Uses pandas DataFrame structure as specified in the spec
- Follows the style guide: Python Blue (#306998), 16x9 aspect ratio
- Font sizes: 20pt for labels/title, 16pt for tick labels
- Y-axis grid with 0.3 alpha for readability
- Simple sequential code (no functions) per plot-generator rules

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

Author: claude[bot]

plots/matplotlib/hist/histogram-basic/default.py

@@ -5,15 +5,16 @@
 
 import matplotlib.pyplot as plt
 import numpy as np
+import pandas as pd
 
 
 # Data
 np.random.seed(42)
-values = np.random.normal(100, 15, 500)
+data = pd.DataFrame({"value": np.random.normal(100, 15, 500)})
 
 # Create plot
 fig, ax = plt.subplots(figsize=(16, 9))
-ax.hist(values, bins=30, alpha=0.8, color="#306998", edgecolor="white", linewidth=0.5)
+ax.hist(data["value"], bins=30, alpha=0.8, color="#306998", edgecolor="white", linewidth=0.5)
 
 # Labels and styling
 ax.set_xlabel("Value", fontsize=20)