[codex] Avoid intrinsic sizing for RTL markdown documents

[omers-oai]

Let's back of the idea to use intrinsic width since it caused issues with SubcomposeLayouts, instead to avoid over expanding stuff we make sure to add maxWidth only when the current layout direction and the needed one for compatibility are not the same.

Also refactored the code a bit so it's maybe cleaner, it's still a mess since interventions are needed all over the place

Codex:

Summary:

• Removes the document-level RTL compatibility sizing wrapper.
• Renders markdown once in BasicMarkdown, with no IntrinsicSize.Max, no document-level SubcomposeLayout, and no top-level forced max width.
• Keeps RTL compatibility block-level: paragraphs/headings use first-strong text direction, and only fill parent width when their detected direction differs from the current layout direction.
• Applies the same conditional RTL width helper to code block expansion points.
• Uses the same opposite-direction width predicate for quote/list measurement, so same-direction content can stay compact while opposite-direction content still gets a full-width line box.
• Keeps quotes/lists/code choosing their internal side when compatibility is enabled.
• Passes the smaller enableRtlCompatibility boolean into width helpers instead of threading the full render options object.
• Keeps markdown RTL helpers in richtext-markdown/.../rtl/RtlCompatibility.kt and UI RTL helpers in richtext-ui/.../rtl/RtlCompatibility.kt.
• Keeps HTML block rendering direct only in compatibility mode so explicit centered HTML can keep its own alignment.
• Enables RTL compatibility in the current RTL preview samples so before/after screenshots exercise the compatibility path.

Root cause:

• The table crash came from asking the whole markdown document tree for intrinsic width. Markdown tables render through SubcomposeLayout, which cannot answer intrinsic measurement.
• A document-level wrapper also made this path more complicated than needed. The simpler generic fix is to not wrap the document for RTL sizing at all; table/custom nodes now use normal measurement only.

Why the fill is conditional:

• Same-direction text already starts on the correct side under the parent layout direction, so forcing fillMaxWidth() just expands compact previews.
• Opposite-direction text still needs a parent-width line box so it can anchor to the far edge.
• Outer alignment alone only moves the child rectangle; it does not change text direction, quote gutter side, or list marker side inside that child.

Testing:

• git diff --check
• ./gradlew :richtext-markdown:allTests
• ./gradlew :android-sample:testDebugUnitTest :android-sample:recordRoborazziDebug
• ./gradlew check

Artifacts:

• Local HTML explanation with diagrams generated under ~/Downloads/codex-artifacts; screenshots were not uploaded to the PR.