docs(recipes): say that a table cell takes a direction too

[DemchaAV]

Why

docs/recipes/text-direction.md still says that text in a table cell carries no direction: the same Hebrew string draws reversed in a cell, Arabic comes out unjoined, and right-to-left text belongs in paragraphs. That stopped being true with #558, which gave DocumentTableStyle a direction(...) of its own. The README and the backend capability matrix already describe table-cell direction; this page was the one place contradicting them.

What changed

• The stale paragraph under Where direction stops gives way to a Tables section: DocumentTableStyle.Builder.direction(...) with LTR / RTL / AUTO, following the cell-style cascade defaultCellStyle → columnStyle → rowStyle → the cell's own withStyle.
• It states the behaviour a reader trips on: AUTO is resolved per cell and over the whole cell; a right-to-left cell takes its right edge only when no textAnchor is set anywhere in its cascade, so a table-wide TOP_LEFT pins it left; the DOCX backend writes no alignment for a plain-text cell; auto columns are measured on the joined Arabic forms; an undeclared cell still draws Hebrew and Arabic in order; a composed-paragraph cell takes the paragraph's direction.
• Where direction stops now lists what still holds: only paragraphs and table cells declare a direction; list items are left-to-right paragraphs, so align(TextAlign.RIGHT) moves them to the right margin but leaves each bullet at the item's left end; column order is not mirrored.
• The new snippet carries a doc-example marker, so DocumentationSnippetCompileTest compiles it.

Verification

Each statement is tied to code and an existing test; no code changed.

• RTL table-cell suites, all green: RtlTableCellTest 8, PptxTableCellDirectionTest 7, DocxTableCellDirectionTest 6, qa RtlAcrossBackendsTest + RtlScenariosVisualTest 15.
• Documentation guards: core com.demcha.documentation.* plus EnginePdfBoundaryTest (links and anchors, recipe catalogue, canonical surface, coverage) 115 green; qa DocumentationSnippetCompileTest 6 + DocumentationExamplesTest 12 green. Breaking the new snippet on purpose turns DocumentationSnippetCompileTest red and names text-direction-table-cell, so the guard really covers it.
• node knowledge/tools/claims/check-claims.mjs --check and node knowledge/tools/routing/check-routes.mjs green; git diff --check clean.
• Not run locally: the full reactor gate, since no code changed; CI runs it on this PR.

Lane: canonical — docs only (docs/recipes/text-direction.md).