PPTX: honor manual chart title layout

[developer0hye]

Summary

• parse title-specific edge-mode c:manualLayout coordinates into ChartTitleLayout
• place PowerPoint chart titles at their authored chart-relative anchors while preserving the existing title band
• add parser and renderer regression coverage plus 300 DPI GT/before/after evidence for pages 8 and 11

Related issue

Fixes #1423

Testing

• cargo fmt --all -- --check
• cargo clippy --workspace --all-targets -- -D warnings
• cargo test --workspace
• cargo check --target wasm32-unknown-unknown -p office2pdf
• cargo check --target wasm32-unknown-unknown -p office2pdf --features wasm
• cargo check --target wasm32-unknown-unknown -p office2pdf --features wasm-cjk-font
• wasm-pack build crates/office2pdf --target web --features wasm
• wasm-pack build crates/office2pdf --target web --features wasm-cjk-font
• wasm-pack test --node --features wasm from crates/office2pdf: 10 passed
• wasm-pack test --node --features wasm-cjk-font from crates/office2pdf: 11 passed
• converted the 15-page PR fix(docx): honor in-cell picture row floors #1407 PPTX and rendered pages 8 and 11 at 300 DPI
• final page 8 and 11 renders are pixel-identical to the committed after evidence source renders: AE 0
• compare_layout.py --audit --json records zero painted-visibility mismatches on both compared pages
• mandatory documentation freshness review: PASS

Visual impact

• No rendered PDF change
• Rendered PDF change or visual evidence added
• Reason: PowerPoint chart titles with edge-mode manual layouts now use the authored position.

Visual audit

• Issue: PPTX chart titles ignore title-specific manual layout and remain centered #1423
• Fixture: PR fix(docx): honor in-cell picture row floors #1407 source PPTX, pages 8 and 11
• Page(s): 8, 11
• Renderer and DPI: pdftoppm, 300 DPI
• Evidence mode: fix
• Layout audit report: assets/bugfixes/issue-1423/layout-audit.json
• Layout audit page count: Pass
• Layout audit text flow: compare_layout ignores outlined Type 3 text metadata and reports visible GT titles as extra output #1415, PPTX combo chart maps a secondary-axis series onto the primary percent axis #1374, PPTX multi-entry right legends use a fixed 14pt row pitch #1434, PPTX column-chart right legends center 9.2pt too low #1435
• Layout audit large shifts: PPTX multi-entry right legends use a fixed 14pt row pitch #1434, PPTX column-chart right legends center 9.2pt too low #1435, PPTX column-chart right legends are right-fitted 11pt too far left #1436
• New follow-up issues found in this audit: PPTX multi-entry right legends use a fixed 14pt row pitch #1434, PPTX column-chart right legends center 9.2pt too low #1435, PPTX column-chart right legends are right-fitted 11pt too far left #1436, PPTX column charts use an uncalibrated automatic vertical plot rectangle #1437, PPTX column-chart right legend keys are 0.56pt too large #1439
• Model vision findings: Both chart titles move from centered to the native left anchors. Page 8 still has compressed legend row pitch, a low and left-shifted legend block, oversized legend keys, and a vertically undersized plot (PPTX multi-entry right legends use a fixed 14pt row pitch #1434-PPTX column charts use an uncalibrated automatic vertical plot rectangle #1437, PPTX column-chart right legend keys are 0.56pt too large #1439). Title weight/color remains different (PPTX chart titles drop rich-text weight and color #1424). Page 11 still lacks the native secondary axis (PPTX combo chart maps a secondary-axis series onto the primary percent axis #1374). Trace-only table and Type3 text findings remain tracked in compare_layout ignores outlined Type 3 text metadata and reports visible GT titles as extra output #1415. Hairlines and emphasis were inspected on 300 DPI crops; the slide-title rule matches, while remaining chart grid geometry and title emphasis are covered by the cited issues.
• GT: assets/bugfixes/issue-1423/gt.jpg
• Before: assets/bugfixes/issue-1423/before.jpg
• After: assets/bugfixes/issue-1423/after.jpg
• Compare: assets/bugfixes/issue-1423/compare.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
• Used Codex/Claude vision to inspect the full GT/output pages, diff, and matched crops
• Inspected matched region crops at full resolution
• Ran compare_layout.py --audit and dispositioned every large text-instance shift and painted-visibility mismatch
• Ran compare_layout.py --audit and dispositioned every large text-instance shift
• 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: 15 pages overall and pages 8/11 compare in source order
Element presence	Remaining: #1374 secondary-axis elements
Position/size	Remaining: #1374, #1434, #1435, #1436, #1437, #1439; Fixed #1423 title anchors
Rotation/flip	No deviation observed
Fill	Matches GT
Stroke/border	Remaining: #1374, #1437 chart grid geometry; title hairline matches GT
Shape outline geometry	Remaining: #1437 automatic plot rectangle; #1439 legend-key dimensions
Text content	Remaining: #1374 visible axis labels; trace-only findings #1415
Font family/weight/style	Remaining: #1424
Text color	Remaining: #1424
Alignment	Fixed: #1423 title alignment; Remaining: #1434, #1435, #1436
Line/paragraph spacing	Remaining: #1434 legend row pitch
Clipping/overflow	Remaining: #1434, #1435 legend/tick overlap

Checklist

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