fix(xlsx): honor data bar rule color written as start/end tags

[developer0hye]

Summary

Data bars ignored the conditional-formatting rule's <color rgb> and always rendered the parser's default steel blue when the rule's children were written as start/end pairs (<color rgb="FF1E2761"></color>, the form produced by openpyxl among others). umya-spreadsheet's DataBar reader only matched Event::Empty, so both the cfvo and color collections came back empty and apply_data_bar_rule fell back to #638EC6 (issue #371).

The reader fix lands in the umya-spreadsheet fork this workspace patches to (branch fix/panic-safety-v2), mirroring ColorScale's reader which already handles both event kinds. It is also upstreamed as MathNya/umya-spreadsheet#347. This PR pins the behavior on the office2pdf side with a regression test that rewrites fixture XML into the start/end-tag form before parsing.

Measured on the sales-dashboard fixture: bars now render the rule navy #1E2761 with column x-positions matching GT exactly (Total column values at x=494.5 vs GT 494.0).

Related issue

Fixes #371

Testing

• cargo test --workspace — green
• Local bulk regression gate — PASS
• New regression test test_cond_fmt_data_bar_color_from_start_end_tag_children (rewrites <cfvo/>/<color/> into start/end pairs and asserts the IR bar color and fill percent)
• umya fork: new unit tests read_child_elements_with_end_tags / read_child_elements_self_closing, full fork suite green
• Converted 06_sales_dashboard_en.xlsx: bars render navy, matching Excel

Visual impact

• No rendered PDF change
• Rendered PDF change or visual evidence added
• Reason:

Visual audit

• Issue: XLSX: data bar ignores the rule color and falls back to default blue #371
• Fixture: 06_sales_dashboard_en.xlsx (synthetic real-world audit set, external)
• Page(s): 1
• Renderer and DPI: pdftoppm, 150 DPI
• Evidence mode: fix
• New follow-up issues found in this audit: XLSX: auto-height rows render ~22% taller than Excel #396 (auto-height rows taller than Excel)
• GT: assets/bugfixes/issue-371/gt.jpg
• Before: assets/bugfixes/issue-371/before.jpg
• After: assets/bugfixes/issue-371/after.jpg

Visual comparison

GT	Before	After

Required inspection

• Rendered all evidence at 150 DPI or higher
• Stored progressive JPEG quality 86 assets with metadata stripped
• Inspected matched region crops at full resolution
• Ran the 5% fuzz pixel-difference sweep
• Inventoried hairlines and border dash styles
• Inventoried font weight, italic, and underline emphasis

Deviation audit

Check	Result
Page count/order	Matches GT
Element presence	Matches GT
Position/size	Remaining: #396 (auto-height rows render 17.15pt pitch vs GT 14.0pt)
Rotation/flip	No deviation observed
Fill	Fixed (bars use the rule navy #1E2761 instead of default blue)
Stroke/border	Matches GT
Text content	Matches GT
Font family/weight/style	Matches GT
Text color	Matches GT
Alignment	Matches GT
Line/paragraph spacing	No deviation observed
Clipping/overflow	No deviation observed

Checklist

• Commits include a Signed-off-by line
• PR scope contains one root cause
• Remaining visual deviations each reference an open issue

🤖 Generated with Claude Code