fix(docx): seat what a row's margins leave of a text cell by the height of its lines

CHANGELOG.md

@@ -8,6 +8,42 @@ follow semantic versioning; release dates are ISO 8601.
 
 ### Public API
 
+- **A DOCX export stands a table text cell's text where the page sets it by the height of its
+  lines, where its row's margins leave less than half a point of what it calls for.** Word and
+  LibreOffice stand an exact line's baseline four fifths of the way down it, and the page sets a
+  cell's line its face's ascent below its top; a row of text cells is moved by its margins by the
+  least its cells call for. A row holding a composed cell is not — its margins would move the
+  composed content too — nor one whose cells call for opposite ways or in a vertical merge, and
+  what the margins left was moved by the text's position from half a point up, and under that
+  not at all. `CobaltRota`'s staff names, beside the day cells its chips are composed in, stood
+  0.25pt low in their rows in Word, 0.2pt in LibreOffice on Windows and 0.19pt in LibreOffice
+  24.2, and its covers label as much. Under half a point, from a tenth, each of the cell's lines
+  is now written shorter and the space after it taller by as much, or the other way as far as
+  that space holds: the cell's content keeps its height and each line its top, and the text
+  moves four fifths of the difference in both editors. Only where every paragraph of the cell is
+  one line, in a face whose letters the export reads — not a standard face it does not embed — and
+  no nearer the letters' tops and feet than three quarters of a point, where Word cuts an exact
+  line's letters on screen. A line alone written shorter keeps a row its height in Word and on
+  Windows, but LibreOffice 24.2 holds a row to its cells' content: written so on a probe, the
+  covers values' lines among them, the covers row, whose tallest content those lines were, came
+  out 0.8pt shorter there (measured).
+  From half a point up the position moves it as before: written by the line instead,
+  `ConsultingInvoice`'s amounts stood nearer the page in their rows in LibreOffice, where the
+  position moves text further than it says, and the rows themselves stand 0.3pt low there, which
+  that overshoot made up for.
+
+  In their rows, `CobaltRota`'s staff names and covers label now stand within 0.08pt of the
+  page's in Word, LibreOffice on Windows and LibreOffice 24.2, every row its height. `CobaltRota`'s
+  median moves from 0.17pt to 0.15pt in Word, its p90 from 0.38pt to 0.31pt, and from 0.08pt to
+  0.06pt in LibreOffice on Windows, its p90 from 0.30pt to 0.22pt; `LumaStudioInvoice`'s from
+  0.14pt to 0.11pt in Word, its long version's from 0.21pt to 0.17pt in Word and from 0.20pt to
+  0.12pt in LibreOffice on Windows. No document's median moves further in Word or in LibreOffice
+  on Windows. Line by line, 21 amounts of `LumaStudioInvoice` and its long version, 0.07pt to
+  0.09pt low in LibreOffice on Windows, stand 0.11pt to 0.13pt high there, and 6, 0.04pt low in
+  Word, 0.08pt high, a step of its grid. LibreOffice 24.2 sets each of `CobaltRota`'s staff rows a twip shorter
+  than the page, holding them to their content, so the rows above the names stand higher there,
+  and the names, seated in their rows, a few hundredths of a point further from the page.
+
 - **A DOCX export holds a shape's row less its borders as wide as Word draws them, and a table's
   row between two others less the rules it holds.**
   - **A shape's borders come off as wide as Word draws them.** A border is written in eighths of a
@@ -64,8 +100,10 @@ follow semantic versioning; release dates are ISO 8601.
   in LibreOffice on Windows and 7 further, by up to 0.15pt — the outlined pair's. In LibreOffice
   24.2 its p90 moves from 0.90pt to 0.52pt and its median from 0.17pt to 0.22pt, 40 of its lines
   nearer and 53 further, by up to 0.3pt: the single-shift labels, now seated in their chips,
-  stand about 0.4pt high with them there, as LibreOffice 24.2 sets the chips 0.25pt higher than
-  the page and Word 0.15pt lower. No other document of the fidelity corpus moves.
+  stand about 0.4pt high with them there, as the rows above the chips come out 0.25pt shorter in
+  all in LibreOffice 24.2 than on the page, and 0.15pt taller in Word; in its own row each chip
+  stands within a tenth of a point of the page's in all three. No other document of the fidelity
+  corpus moves.
 
 - **A DOCX export counts a table's rules as Word and LibreOffice do, and holds a cell's margins and
   a chip composed in it to the twip the page gives them.**

docs/architecture/backend-capability-matrix.md

@@ -80,7 +80,7 @@ Payload records live in `core` under
 | Gradient strokes | ✅ `PdfPathPainter` (pattern stroking colour) | ✅ `PptxGradientFill` (native `ln`/`gradFill`) | ❌ |
 | Image — STRETCH / CONTAIN / COVER fit (`ImageFragmentPayload`) | ✅ `PdfImageFragmentRenderHandler` | ✅ `PptxImageFragmentRenderHandler` (COVER via the picture source crop) | ✅ `DocxSemanticBackend.writeImage` (the box comes from `NodeDefinitionSupport.resolveImageDimensions`, the same rule layout applies to `width` / `height` / `scale` and the content-width clamp; CONTAIN is embedded at its fitted size, COVER via the picture source crop as in PPTX, and the picture type is read from the bytes; its left margin and padding are not written, and a picture drawn beside its text is fitted to its box with its padding in it — each named in the report) |
 | Barcode / QR (`BarcodeFragmentPayload`) | ✅ `PdfBarcodeFragmentRenderHandler` (vector: the ZXing bit matrix filled as merged rectangles) | ✅ `PptxBarcodeFragmentRenderHandler` (native freeforms: the same ZXing bit matrix as merged rectangles) | ⚠️ `DocxSemanticBackend.writeBarcode` (a PNG picture of the same ZXing bit matrix through `BarcodeMatrices`, one pixel a cell, in the symbol's two colours with their alpha and at the node's size, its data as the picture's description; it scans, but its data is part of the picture rather than editable, reported `APPROXIMATED`, which also names a link, a transform or its left margin and padding as not carried; an `anchor` is a bookmark on its paragraph; in a page zone it is skipped) |
-| Table rows — resolved cells, row/col spans, two-pass fill/border paint (`TableRowFragmentPayload`) | ✅ `PdfTableRowFragmentRenderHandler` + row grouping in `PdfFixedLayoutBackend` | ✅ `PptxTableRowFragmentRenderHandler` + row grouping in `PptxFixedLayoutBackend` (positioned rectangles, edge lines, and text frames — never native PPTX tables, which re-lay-out content) | ⚠️ `DocxSemanticBackend.writeTable` (a real Word table on the grid `TableGrid` resolves: `colSpan` maps to `w:gridSpan`, `rowSpan` to `w:vMerge`, and the cascaded `DocumentTableStyle` text style reaches the cell's runs; the cell's fill maps to `w:shd` and its stroke to `w:tcBorders` — the engine's default 1pt black rule where the table states none, not Word's thinner grid — its padding to `w:tcMar`, less above and below the room Word makes for the horizontal rules (half of a rule between two rows, the lower row's, to each; the rules above and below the table whole to their row), each as wide as Word draws it, in eighths of a point, and counted as both editors count it, two and a half twips an eighth rounded down (a rule between two rows shared in whole twips, the row above it taking half rounded down; a cell's top and bottom margins rounded to the twip together), a row held at the page's height less the most any of its cells takes, its margins and the rules it holds — between two others, the rest of its own above and half that of the cell under it; LibreOffice makes room at the edge between two rows for the heavier of their rules, where Word makes it for the lower row's, and under a row ruled heavier than it a row stands the difference lower there; a row of text cells moved by its top and bottom margins together, from Word's seat four fifths of the way down an exact line onto the page's baselines, by the least its cells' lines call for and no further than the margins hold — not a row holding a composed cell, one the layout did not measure, one in a vertical merge or whose cells call for opposite ways, nor a least call under a tenth of a point — and what the margins leave of a cell's call, half a point and more, moved by its text's position; a row's cells at the row's smallest top and bottom margins, since both editors give every cell the row's largest, the rest of each cell's padding as space above its first paragraph and below its last, down to the largest margin a cell opening with a table or in a vertical merge keeps; the cascaded `textAnchor` maps to `w:vAlign` on every cell and to `w:jc` on a text cell's paragraph, with the engine's default — the vertical middle, on the left, or on the right for a right-to-left cell — and `DEFAULT` at the bottom left, as the renderer draws it; a composed cell is written by the same writers that write its node anywhere, so one built from an image, a list or a table carries it — a nested table is a real `w:tbl` taking the width of the column it sits in, less its own margins and padding, which is the column's rather than the one the page gives it, since the layout reports a composed cell's content under the owner's path; the paragraph Word requires after a nested table is hidden where it ends its cell holding nothing and no space; a translucent fill is flattened against the colour the page paints under the cell, and a translucent rule against the cell's fill where it has one, since `w:shd` and `w:tcBorders` are opaque, and the table's report note names it (`translucency`); Word re-paginates, so the export states where the layout breaks: every row the layout placed is `w:cantSplit`, `repeatHeader(n)` rows are `w:tblHeader` and keep with the row under them, and a row of blocks is kept whole the same way; the paragraph Word requires after a document's closing table is an ordinary one where the last page has room for two lines below it, so a reader can type below the table, and otherwise a point tall with its mark hidden, so it opens no blank page, reported `APPROXIMATED` since text typed at the end then goes into the table's last cell) |
+| Table rows — resolved cells, row/col spans, two-pass fill/border paint (`TableRowFragmentPayload`) | ✅ `PdfTableRowFragmentRenderHandler` + row grouping in `PdfFixedLayoutBackend` | ✅ `PptxTableRowFragmentRenderHandler` + row grouping in `PptxFixedLayoutBackend` (positioned rectangles, edge lines, and text frames — never native PPTX tables, which re-lay-out content) | ⚠️ `DocxSemanticBackend.writeTable` (a real Word table on the grid `TableGrid` resolves: `colSpan` maps to `w:gridSpan`, `rowSpan` to `w:vMerge`, and the cascaded `DocumentTableStyle` text style reaches the cell's runs; the cell's fill maps to `w:shd` and its stroke to `w:tcBorders` — the engine's default 1pt black rule where the table states none, not Word's thinner grid — its padding to `w:tcMar`, less above and below the room Word makes for the horizontal rules (half of a rule between two rows, the lower row's, to each; the rules above and below the table whole to their row), each as wide as Word draws it, in eighths of a point, and counted as both editors count it, two and a half twips an eighth rounded down (a rule between two rows shared in whole twips, the row above it taking half rounded down; a cell's top and bottom margins rounded to the twip together), a row held at the page's height less the most any of its cells takes, its margins and the rules it holds — between two others, the rest of its own above and half that of the cell under it; LibreOffice makes room at the edge between two rows for the heavier of their rules, where Word makes it for the lower row's, and under a row ruled heavier than it a row stands the difference lower there; a row of text cells moved by its top and bottom margins together, from Word's seat four fifths of the way down an exact line onto the page's baselines, by the least its cells' lines call for and no further than the margins hold — not a row holding a composed cell, one the layout did not measure, one in a vertical merge or whose cells call for opposite ways, nor a least call under a tenth of a point — and what the margins leave of a cell's call, half a point and more, moved by its text's position, and less, from a tenth of a point, by the height of its lines, each written shorter and the space after it taller, or the other way as far as that space holds, which keeps the cell's content as tall — where every paragraph of the cell is one line, in a face whose letters the export reads, and its letters stay clear of the line's top and foot; a row's cells at the row's smallest top and bottom margins, since both editors give every cell the row's largest, the rest of each cell's padding as space above its first paragraph and below its last, down to the largest margin a cell opening with a table or in a vertical merge keeps; the cascaded `textAnchor` maps to `w:vAlign` on every cell and to `w:jc` on a text cell's paragraph, with the engine's default — the vertical middle, on the left, or on the right for a right-to-left cell — and `DEFAULT` at the bottom left, as the renderer draws it; a composed cell is written by the same writers that write its node anywhere, so one built from an image, a list or a table carries it — a nested table is a real `w:tbl` taking the width of the column it sits in, less its own margins and padding, which is the column's rather than the one the page gives it, since the layout reports a composed cell's content under the owner's path; the paragraph Word requires after a nested table is hidden where it ends its cell holding nothing and no space; a translucent fill is flattened against the colour the page paints under the cell, and a translucent rule against the cell's fill where it has one, since `w:shd` and `w:tcBorders` are opaque, and the table's report note names it (`translucency`); Word re-paginates, so the export states where the layout breaks: every row the layout placed is `w:cantSplit`, `repeatHeader(n)` rows are `w:tblHeader` and keep with the row under them, and a row of blocks is kept whole the same way; the paragraph Word requires after a document's closing table is an ordinary one where the last page has room for two lines below it, so a reader can type below the table, and otherwise a point tall with its mark hidden, so it opens no blank page, reported `APPROXIMATED` since text typed at the end then goes into the table's last cell) |
 | Clip region open/close (`ShapeClipBegin/EndPayload`) | ✅ `PdfShapeClipBegin/EndRenderHandler` (CLIP_BOUNDS + CLIP_PATH) | ✅ `PptxClipSafety` + raster fallback in `PptxFixedLayoutBackend` — a provably no-op clip (padded content that cannot be cut) skips the fallback entirely and stays native, editable shapes; a clip that can cut ink renders through the PDF backend into one transparent picture on the clip bounds (pixel-exact, not editable as shapes; run-level link hotspots are not emitted and custom fragment handlers do not apply inside the picture; `Builder.clipRasterFallback(false)` restores unclipped vectors + warning; the raster targets a 2048px long edge, clamped to between native size and 4x, so a region larger than that is rendered at native resolution rather than downscaled — which also means its transient memory grows with the clip instead of stopping at the target (a 3370pt A0-landscape region costs ~45MB while rendering, against ~17MB for anything up to 2048pt); a true vector clip is tracked in [#413](https://github.com/DemchaAV/GraphCompose/issues/413)) | ⚠️ inline fallback + one-time capability warning; the report names a clip that cuts what its layers paint, measured from the layout's fragments by `DocxClipInk` — a clip that cuts nothing (an icon inside its box, a disc's initials, a photo filling its circle) is not named; a picture that fills a container clipped to an ellipse takes the ellipse as its geometry, which both editors crop it to; a badge's glyph — a smaller picture in a painted container that clips it to its outline (`CLIP_PATH`) and holds nothing else but drawing — is drawn by `DocxDrawings` as a floating picture over the outline, where the layout places it, reported `APPROXIMATED` — inside a filled panel the badge and its glyph are drawn in front of the shading; an icon picture beside its text in an unpainted container or a layer stack is drawn the same way; a filled or outlined rectangle or rounded rectangle holding text, composed in a table cell, which has no place in the layout to be drawn at, is written as a panel — a one-cell table in its fill and outline, its corners squared and reported, its row held at least the outline's height less its borders and margins, which keep inside it, and a one-line label the shape centres top to bottom on a line taller than the room Word leaves its content cut alike on both sides to that room, no closer to its letters than three quarters of a point, and seated where the page sets it, from the shape's top where the line is taller than its outline and Word sets it on the shape's middle, and a label it holds whole written at the line height that stands its text on the page's baseline, as far as its letters and the room allow, by a tenth of a point or more and not in a standard face the export does not embed — its row held and its label cut in whole twips rounded down, as the row the cell is in holds the page's height rounded once, and what its letters keep the label past that room taken out of the margins of the cell it is in, where it is all that cell holds and the cell all its row holds; the rest of what a composed cell draws (an icon, a tile, a disc) is the table's own drawing and is drawn by `drawCellDrawing` where the layout puts it, anchored as a rectangle is |
 | Timeline rail — one logical connector line resolved from marker and entry anchors after layout (`ShapeFragmentPayload` per page) | ✅ `PdfShapeFragmentRenderHandler` — one fragment per page, spliced beneath the markers | ✅ `PptxShapeFragmentRenderHandler` — same payload, same per-page fragments | ⚠️ `DocxDrawings` — the rail is read from the resolved layout's pass fragments and drawn per page as a `line` shape, and the markers as the shapes they are, anchored as a rectangle is: beside an entry's text they move with it when the text above is edited |
 | Transform open/close — rotate/scale about fragment centre (`TransformBegin/EndPayload`) | ✅ `PdfTransformBegin/EndRenderHandler` | ✅ `PptxTransformBegin/EndRenderHandler` (group shape; rotation and centre-pivot scaling via the exterior/interior frame ratio) | ⚠️ inline fallback + one-time capability warning; a turned shape container is written upright, and the report names its transform — in its drawn outline's note, or on its own where the outline draws nothing |