fix(docx): anchor what a table's composed cell draws in that cell

CHANGELOG.md

@@ -8,6 +8,71 @@ follow semantic versioning; release dates are ISO 8601.
 
 ### Public API
 
+- **A DOCX export anchors what a table's composed cell draws in that cell, so it moves with the
+  cell's row when the text above is edited.**
+  - Such a drawing has no node of its own — a composed cell's content is laid out under its
+    table, its drawings among the table's own fragments — and stood in the paragraph whose text
+    it was nearest, or on the page where it stood beside none. Six invoices' service tiles were
+    placed from the page's edges: edited above, every line row moved and the tiles did not, and
+    LibreOffice 24.2, which sets those rows 1.96pt shorter than the page does, left each tile
+    further out of its row than the last: 0.94, 2.94, 4.89, 6.84 and 8.79pt down the five rows.
+  - The cell whose box the layout placed the drawing in now stands for the block holding it, and
+    the drawing is anchored in the first paragraph of that cell able to carry it, placed from
+    that cell's text column and the paragraph's top, exactly as a drawing a node paints is. A
+    drawing no cell's box holds — one the table paints across its cells — keeps the
+    nearest-text rule, as does one whose cell writes no paragraph that can carry it.
+  - A cell set to the middle or the bottom takes one only where the page fills its box, since
+    LibreOffice 24.2 sets a cell carrying a drawing — and the cell holding its table — from its
+    top. Measured in Word 16.0.20527 and LibreOffice 24.2: with room to centre in, such a cell had
+    its own text set 4pt and 23.75pt higher and the text of the cell holding its table 43.7pt
+    higher, while a cell the page fills moved no line in either editor, and nor did one holding no
+    text whatever room it was left. The cell the page fills is excused its own alignment whatever
+    it holds — the page leaves it nothing to centre — while a cell *inside* it must hold nothing
+    an editor would set lower: no text, a link's included, no picture, no paragraph border and no
+    table of its own.
+  - The same rule now holds for a drawing the text nearest it carries, which it did not: a
+    neighbouring cell takes one only where it, and each cell holding its table, sets its content
+    from its top. It was held to its own alignment alone, and a cell inside one set to the middle
+    took a drawing LibreOffice would then have moved its row's text for.
+  - The cell that carries the drawing is written to be read from its top, which it holds no text
+    to be read any other way by. Word centres a cell set to the middle along with the drawing its
+    paragraph carries: measured in Word 16.0.20527, a tile carried by such a cell in a row four
+    lines tall stood 7.10pt below where the page puts it, and 0.30pt from it once the cell was
+    read from its top; in a row the cell's own content fills — every one the fidelity corpus has
+    — the two are the same place and nothing in the file moves.
+  - A cell composed of a node that stands in more than one place carries none either: such a node
+    is laid out once, so the lines of the paragraphs written for it in the second cell are the
+    first cell's, and a cell that cannot say where its own content stands cannot place a drawing
+    from it. Nor does a cell of a repeated header row: Word repeats such a row, and what is
+    anchored in it, on every page the table reaches, beside the copy the layout placed there.
+    A drawing any of these refuses keeps the nearest-text rule, as one no cell's box holds does —
+    the paragraph whose text it stands nearest, within reach, and the page where it stands beside
+    none. The report's note names all four.
+  - Of the 190 drawings the fidelity corpus composed in table cells, 165 are now anchored in
+    their cell. The 25 left are `PaymentsInvoice`'s, `WorkspaceInvoice`'s and
+    `MerchantInvoice`'s, whose rows nest a row inside a cell: the cell between the composed cell
+    and the drawing's own is set to the middle, and the layout does not say how much room it is
+    left. Two notes are gone with the change: the shapes `MeteredInvoice`'s longer form anchored
+    in a cell for want of another paragraph on the page, which Word might have printed clipped to
+    it, now stand in the cell that holds them.
+  - Measured in Word 16.0.20527 and LibreOffice 24.2 on `MeteredInvoice`: the tile stood 10.84pt
+    above its line's title on the page, 9.90, 7.90 and 5.95pt above it down the rows in
+    LibreOffice before, and 10.85pt above it in every row after; Word keeps it within 0.03pt, and
+    0.5pt further across, where Word also sets that row's text.
+
+- **A drawing is placed from its paragraph's top only where Word reads that offset back.**
+  - Measured in Word 16.0.20527: an offset of 0.05, 0.13, 0.21, 0.25 or 0.29pt above a paragraph
+    is drawn where it says but reported to a reader as one of Word's position keywords
+    (−999999, −999997, −999994, −999993), while 0.30pt and every larger offset — 0.40, 0.50,
+    0.60, 0.75, 0.97 — is reported as itself. A shape standing less than 0.30pt above its
+    paragraph is placed at its top, where it practically stands; one standing further keeps its
+    own offset. A stroke's width was allowed before, which squared the 0.97pt a service tile
+    needed to nothing and stood it 0.96pt low.
+  - A table cell is given no drawing standing 0.30pt or further above its paragraph, on the
+    nearest-text rule: a 20.5pt rule placed a stroke's width above its paragraph in a cell moved
+    that row's text 1.8pt up in the Linux LibreOffice the build checks with, and such an offset is
+    now written rather than squared to nothing.
+
 - **A DOCX export anchors a drawing in a paragraph of the block it belongs to, so it moves with
   that block when the text above is edited.**
   - A shape stood in the paragraph whose text was nearest it, within 48pt, rising above that
@@ -25,8 +90,8 @@ follow semantic versioning; release dates are ISO 8601.
     sitting in one, carries none: the block's next
     paragraph able to place it takes the drawing, or else the next block up. A drawing no node
     paints — a timeline's rail — and one whose blocks write no such paragraph on its page go to
-    the paragraph nearest it there. What a table's composed cell draws keeps the nearest-text
-    rule. The report's note on each drawing says how it is anchored.
+    the paragraph nearest it there. What a table's composed cell draws goes to the cell whose box
+    holds it (above). The report's note on each drawing says how it is anchored.
   - Measured in Word 16.0.20527 and LibreOffice 24.2: a shape anchored in a table cell's
     paragraph stands where both say — rising 36pt above its row, hanging below its table, out of
     its cell, taller than its row, in an exact row or a nested table, in front of the text or