LibWeb: Use FfiDisplay directly for table roles

[kalenikaliaksandr]

Rust layout classified displays into table-specific enum before checking
their roles. This duplicated predicates already available on FfiDisplay
and forced every consumer through an unnecessary conversion layer.

Remove FfiTableDisplay and table_display_of. Tree construction and
formatting context selection, node facts, and table grid construction
now query FfiDisplay directly. Spec-level grouping helpers remain only
where they express table concepts instead of mirroring display roles.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro Plus

Run ID: 5e8420d9-66bd-4054-9bd0-7903b53ce37d

📥 Commits

Reviewing files that changed from the base of the PR and between fead442 and 06c5069.

📒 Files selected for processing (8)

• Libraries/LibWeb/Layout/TreeBuilder.cpp
• Libraries/LibWeb/Rust/src/layout/formatting_context.rs
• Libraries/LibWeb/Rust/src/layout/layout_node_arena.rs
• Libraries/LibWeb/Rust/src/layout/layout_state.rs
• Libraries/LibWeb/Rust/src/layout/node_facts.rs
• Libraries/LibWeb/Rust/src/layout/style_facts.rs
• Libraries/LibWeb/Rust/src/layout/table_formatting_context.rs
• Libraries/LibWeb/Rust/src/layout/tree_builder.rs

💤 Files with no reviewable changes (3)

• Libraries/LibWeb/Layout/TreeBuilder.cpp
• Libraries/LibWeb/Rust/src/layout/layout_node_arena.rs
• Libraries/LibWeb/Rust/src/layout/style_facts.rs

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📝 Walkthrough

Walkthrough

The layout system now classifies table roles directly from FfiDisplay values. The obsolete FfiTableDisplay APIs and saved-absolute-position FFI transfer path were removed. Box replacement preserves saved absolute-position inputs through local arena operations.

Changes

Layout classification and replacement

Layer / File(s)	Summary
Direct display classification Libraries/LibWeb/Rust/src/layout/style_facts.rs, Libraries/LibWeb/Rust/src/layout/formatting_context.rs, Libraries/LibWeb/Rust/src/layout/layout_state.rs, Libraries/LibWeb/Rust/src/layout/node_facts.rs	Removed FfiTableDisplay classification APIs. Formatting-context and layout-state checks now use direct FfiDisplay predicates.
Table tree and fixup classification Libraries/LibWeb/Rust/src/layout/table_formatting_context.rs, Libraries/LibWeb/Rust/src/layout/tree_builder.rs	Table traversal, wrapper generation, parent and child fixup, and replaced-element handling now use current or pre-transformation FfiDisplay values.
Replacement state transfer cleanup Libraries/LibWeb/Rust/src/layout/tree_builder.rs, Libraries/LibWeb/Rust/src/layout/layout_node_arena.rs, Libraries/LibWeb/Layout/TreeBuilder.cpp	Box replacement copies saved absolute-position inputs locally. The Rust arena wrapper and C++ FFI call were removed.

Estimated code review effort: 3 (Moderate) | ~25 minutes

Possibly related PRs

• LadybirdBrowser/ladybird#10942: Continues the same style-derived display refactor in the Rust layout modules.
• LadybirdBrowser/ladybird#10927: Shares table-layout and tree-builder refactoring.
• LadybirdBrowser/ladybird#10928: Removes the saved-absolute-position transfer API used by related layout infrastructure.

🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description check	✅ Passed	The description directly matches the changes to remove FfiTableDisplay and use FfiDisplay for table-role handling.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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