feat(matplotlib): implement bar-basic

[github-actions]

Implementation: bar-basic - matplotlib

Implements the matplotlib version of bar-basic.

File: plots/bar-basic/implementations/matplotlib.py

Parent Issue: #612

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🤖 impl-generate workflow

[claude]

AI Review - Attempt 1/3

Quality Score: 92/100

Criteria Checklist

• VQ-001: Axes labeled correctly ("Product Category", "Sales ($)")
• VQ-002: Grid is subtle (alpha=0.3, y-axis only)
• VQ-003: Elements clear (bars with good contrast and size)
• VQ-004: No overlapping labels (all text readable)
• VQ-005: Legend N/A (single series, no color mapping)
• VQ-006: Colorblind safe (single blue color #306998)
• VQ-007: Image size correct (16:9 aspect ratio, dpi=300)
• VQ-008: Title present and centered
• CR-001: Data accurate (categories as x-axis, values as bar heights)
• CR-002: Spec compliance (consistent widths, value labels, single color, adequate spacing)

Note: Code quality criteria (CQ-001 through CQ-005) are N/A per KISS style guidelines for plot implementations.

Issues Found

None - implementation meets all quality criteria.

Spec Compliance Details

Requirement	Status
Bar widths consistent	Yes (width=0.6)
Value labels on bars	Yes ($XX,XXX format above bars)
Single color for all bars	Yes (#306998 Python blue)
Adequate spacing between bars	Yes (clean visual separation)
Y-axis starts at 0	Yes (set_ylim(bottom=0))

Code Quality

• Follows matplotlib library rules (ax methods, not plt functions)
• Uses correct save format (dpi=300, bbox_inches='tight')
• Clean KISS style without unnecessary functions or classes
• Removed top/right spines for cleaner appearance

Verdict: APPROVED