fix: improve no-unreachable-media-conditions for nested at-rules

[bartveneman]

closes #97

Summary

This PR improves no-unreachable-media-conditions that detects when nested @media and @container queries create contradictory conditions that make the inner rule unreachable.

Key Changes

• **improve rule: no-unreachable-media-conditions

  • Detects contradictory bounds when nesting @media or @container at-rules
  • Walks up the ancestor chain to collect bounds from parent at-rules of the same type
  • Reports violations on the inner (problematic) rule, not the outer one
  • Handles both min/max syntax (min-width: 100px) and range syntax (width >= 100px)
  • Skips analysis when prelude is too complex (not/or operators)

• Comprehensive test suite

  • 30+ test cases covering valid and invalid scenarios
  • Tests for @media with width/height features
  • Edge cases: mixed units, equal bounds, multi-level nesting, independent violations

• Utility function: collect_bounds_from_prelude (src/utils/media-conditions.ts)

  • Parses at-rule preludes and extracts numeric bounds from features
  • Returns null for complex queries that can't be safely analyzed
  • Returns empty array or array of bounds depending on feature presence
  • Supports both @media and @container at-rules

Implementation Details

• Container name handling: For @container rules, only ANDs bounds when both parent and child use the same non-empty container name. Unnamed containers are treated independently since they apply to different ancestor container elements.
• Contradiction detection: Reuses existing find_contradictory_feature utility to identify impossible conditions
• Avoidance of double-reporting: Skips analysis if the current rule or ancestors are already contradictory (handled by no-unreachable-media-conditions)
• Complexity handling: Safely aborts analysis for comma-separated queries and not/or operators to prevent false positives

https://claude.ai/code/session_019rwTo8FJ5pULsuchZ3f2PN

[codecov-commenter]

Bundle Report

Changes will increase total bundle size by 3.42kB (5.37%) ⬆️⚠️, exceeding the configured threshold of 5%.

Bundle name	Size	Change
stylelintPlugin-esm	67.05kB	3.42kB (5.37%) ⬆️⚠️

Affected Assets, Files, and Routes:

view changes for bundle: stylelintPlugin-esm

Assets Changed:

Asset Name	Size Change	Total Size	Change (%)
index.mjs	3.42kB	62.69kB	5.76% ⚠️

Files in index.mjs:

• ./src/rules/no-unreachable-media-conditions/index.ts → Total Size: 5.13kB

• ./src/utils/media-conditions.ts → Total Size: 7.64kB

[codecov-commenter]

Codecov Report

❌ Patch coverage is 93.44262% with 4 lines in your changes missing coverage. Please review.
✅ Project coverage is 97.85%. Comparing base (a42d1fb) to head (2c42db3).

Files with missing lines	Patch %	Lines
src/utils/media-conditions.ts	82.60%	4 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #98      +/-   ##
==========================================
- Coverage   98.15%   97.85%   -0.30%     
==========================================
  Files          34       34              
  Lines         920      981      +61     
  Branches      234      250      +16     
==========================================
+ Hits          903      960      +57     
- Misses         14       18       +4     
  Partials        3        3              

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