feat: CSS/SCSS/LESS parsing with cross-language STYLES edges and conflict detection

[CodeBlackwell]

Summary

• CSS/SCSS parsing with Tree-sitter: selector extraction, specificity computation [a,b,c], single-file override detection (specificity, !important, BEM, source order), custom properties, @media/@keyframes/@import, SCSS $variables/@mixin/@include/& nesting, Vue <style> block delegation
• Cross-language STYLES edges: extract className from JSX/TSX and class from Vue <template>, post-build linking pass connects components to CSS selectors, CSS Modules resolution (styles.foo → .foo with camelCase-to-kebab)
• Cross-file conflict detection: heuristic flagging of same-name selectors across files via POTENTIAL_CONFLICT edges with specificity comparison and confidence metadata
• LESS support: regex-based parser (no tree-sitter grammar available) for selectors, @variables, .mixins(), @import
• 3 new MCP query patterns: styles_of, styled_by, conflicts_of
• Visualization: STYLES (blue) and POTENTIAL_CONFLICT (red) edge styling with legend entries

New Edge Types

Edge	Source	Target	Purpose
OVERRIDES	Winning CSS selector	Losing CSS selector	Single-file specificity/cascade override
STYLES	JSX component / Vue file	CSS selector	Cross-language class reference
POTENTIAL_CONFLICT	CSS selector	CSS selector	Cross-file same-name selector conflict

Architecture

Two-phase approach keeps the parser stateless:

1. Per-file: Extract class references during parsing, store in node extra metadata
2. Post-build: link_css_styles() and detect_cross_file_conflicts() query the graph and create cross-file edges

Both phases run automatically in full_build() and incremental_update().

Test Plan

• 229 tests passing (47 new)
• ruff check clean
• mypy clean
• TestJSXClassExtraction — static className, CSS Module refs, dynamic skip, function attachment
• TestVueTemplateClassExtraction — static class, dynamic :class skip, style+template coexistence
• TestLESSParsing — selectors, @variables, @import, .mixins, language tagging
• TestCSSStylesLinking — cross-file STYLES edges, Vue same-file linking, missing selector no-op
• TestCrossFileConflicts — same-selector conflict, unique selector no-conflict, metadata validation
• TestCamelToKebab — camelCase conversion correctness
• Full graph rebuild exercises linking pass end-to-end

[tirth8205]

Closing — CSS/SCSS support scope is too broad for the current architecture. Tree-sitter CSS parsing doesn't produce meaningful function/class nodes for the knowledge graph.

[tirth8205]

CSS/SCSS/LESS parsing with cross-language STYLES edges is not in main — parser.py has no CSS/SCSS/LESS support, no STYLES edge type, and no styles_of/styled_by/conflicts_of query patterns. This is a substantial PR (2135 additions) with well-defined scope. Worth reviving — it would be valuable for frontend-heavy codebases. The two-phase approach (per-file extraction + post-build linking) is architecturally sound.

[CodeBlackwell]

Revived and rebased onto current main (the tools.py split + parser/graph refactors). Beyond resolving conflicts, this tightens the STYLES linking based on a review pass:

• Import-scoped edges — components now link only to stylesheets they actually import (same-file or via css_import_files recorded on the File node), replacing the previous global class-name match that produced false edges across unrelated CSS files.
• Robust selector indexing — compound (.btn.active), descendant (.card .btn), and pseudo (.btn:hover) selectors now match a plain className via a single token regex.
• Hoisted a per-file import map out of an inner loop; corrected a stale docstring.

Full suite green (1437 passed), ruff + mypy clean on touched files. Happy to adjust the scoping heuristic if you'd prefer a different policy for global (non-module) CSS.