fix(docx): say what an export with no layout leaves to Word, and count an anchor's nodes off the document

[DemchaAV]

Why

An export with no layout behind it — a document the engine refused to lay out, whose export
falls back to what the document states, or a bare export(graph, context) — told the caller
less than it lost, and in part the wrong thing:

• A drawing was dropped as having "its geometry has no semantic Word analogue". A drawing stands
  where the layout puts it, and with a layout the same shape is drawn; the reason was the missing
  layout. An unpainted shape (addCircle(60)) carried that reason with a layout too, though the
  page draws nothing of it.
• The section's note named line heights, the space between lines and auto column widths, and not
  the rest only a layout places or keeps (measured on the merged tree): a centred alignment and a
  stack's centred layer are written at the left, a SPACE_BETWEEN row as columns Word sizes, and
  no keep is written — keepNext 0 and keepLines 0 against 2 and 3 with the layout, since each
  waits for the layout to show the page held the block on one page.

Three more things went unsaid or were missing, with a layout as well:

• With metadata set, docProps/app.xml still read <Application>Apache POI</Application>; the
  metadata's creator and producer were not written.
• A table POI creates has no w:tblGrid, and one whose columns were left to Word kept none: a row
  with no layout, top-level and nested, a composed row the layout does not place, a chart's data
  table. CT_Tbl requires the element.
• An anchor declared in two composed cells of one table was counted as one node: the layout
  registers both markers under the table's path. The file kept one bookmark and the report said
  nothing. An anchor in a table header row the page repeats is registered on every page the header
  is drawn on; the page's link and page reference go to the last repeat (measured: a reference
  reading "5" on a five-page table), Word's bookmark sits in the one row the file holds — on page
  1, and the field reads 1 once Word updates it (measured with Word COM). That went unsaid too.

What changed

• Why a drawing is dropped (droppedBecause, now an instance method): a drawing that paints
  nothing — no fill, no fill paint, no stroke wider than zero (paintsNothing) — "paints nothing
  a shape could show"; with no layout, a drawing has "no layout behind the export, nothing says
  where the page draws it". The gradient and unknown-kind reasons stay first. A horizontal rule is
  still written as a rule without a layout.
• The no-layout note (DocxWithoutLayout.note, new): the old sentence stays as it was for a
  section that holds none of the rest, so existing exports read the same. Each clause is added
  only where the section holds one: a row its arrangement or a growing spacer divides (an empty
  row writes nothing and is not counted); an alignment other than LEFT, or a stack's or a shape
  container's layer set in by its alignment or its offset, "written from the left"; and "Word is
  not told to keep what the page keeps from a page break" with the kinds the section has — a block
  kept together or with the next, a table's row in one piece, a row of columns. A block or a row
  composed in a table cell is kept by its table row, laid out or not, and is not counted; a
  repeated header row is still kept with the row under it, which needs no layout. The keeps stay
  unwritten, as before (withoutALayoutNothingIsKnownToBeOnOnePage): only the layout knows a
  block fits on a page, and a document it refused may hold a row taller than one, which no page
  holds whole however Word is told to keep it.
• Metadata (applyMetadata): the creator is the extended Application (the producer where no
  creator is set), as the PPTX backend writes it. A Word file has no producer field; a producer
  the caller set, other than the application written, is named (DROPPED, producer). The
  producer every DocumentMetadata starts with is not: a session setting only its creator would
  have been told on every export.
• Grid (withAGrid, at the two places tables are made): every table starts with an empty
  w:tblGrid, which the column writers fill as before, between w:tblPr and the rows. Measured in
  Word and LibreOffice, word by word: a top-level and a nested SPACE_BETWEEN row, and a table of
  auto columns with and without a width, each with no grid and with an empty one, stand the same in
  both editors (equal gridCols moved LibreOffice's by 0.05pt); so do the committed
  WordExportCompanion file and its re-render.
• Anchor counting (DocxAnchorDeclarations, new): nodes are counted off the document — each
  node declaring an anchor, read off a table of the kinds that declare one (DECLARING, exact
  classes: node records are final), through the content a table's cells are built from — and the count is
  the larger of that and the paths the layout registers the anchor under
  (DocxLayoutMetrics.anchorPaths), which a node of the caller's own kind declares through and
  the document cannot tell. DocxLayoutMetrics.anchorsDrawnAgain gives the anchors one path
  registers on more than one page. An anchor one node declares, in a repeated header row, drawn on
  two pages or more and bookmarked, is named.

Verification

• ./mvnw -B -ntp test -f render-docx/pom.xml — BUILD SUCCESS, render-docx 1720 tests (+14):
  DocxWithoutLayoutTest (new, 8: the note unchanged for paragraphs; an arranged and a grown row;
  an alignment, a stack's centred layer, an offset one, a shape container's, and left ones not
  named; each keep kind, all three together, an empty row; a row and a block composed in a cell
  not named; each drawing's reason without a layout, a filled path and a paint fill included, a
  rule not dropped; an unpainted circle, path and line and a zero-width stroke; an empty grid
  top-level and nested, in schema order), DocxSemanticBackendTest +2 (the creator as
  Application, a producer named; the default, a producer standing alone and a creator set alone
  not named), DocxLinkTest +2 (two cells of one table, two paragraphs and a paragraph with a
  drawn circle; a repeated header — direct, inside a block, on one page, a drawn circle),
  DocxReportedLossesTest +1 (an anchor a node of the caller's own kind declares),
  DocxAnchorDeclarationsTest (new: DECLARING holds every node kind GraphCompose ships with an
  anchor component but the page reference, read off the class scan the field ledger uses).
• 36 sabotages, each undoing one part — the cell walk, the header rows and the flag carried into
  them, a header drawn once, the bookmark condition, the repeat note, the document count, the
  layout's paths, each drop reason, the zero-width stroke, each paint field, the old note, each
  clause and its conditions (stacks, shape containers, offsets, left layers, cells, empty rows),
  the Application, the producer's fallback, its note both ways and the default producer, the
  grid in the body and in a cell, a kind left out of DECLARING (two) — all caught.
• Corpus: 62/62 DOCX byte-identical, docProps included; report notes 1244 → 1244 (no corpus
  document is exported without a layout, sets metadata or declares an anchor twice).
• WordExportCompanion's committed DOCX is re-rendered: its Application now reads GraphCompose,
  and its chart's data table has an empty grid. Converted with Word and LibreOffice, the old and
  the new file put every word (186 and 183) at the same place.
• ./mvnw -B -ntp clean verify — BUILD SUCCESS (core 821, render-docx 1720, examples 93, qa 1820);
  the knowledge pack's --check, stability-doc, claims and routes guards pass.

Lane: render-docx (semantic backend) — report and package metadata; no layout change.