Add tests for container queries with name-only syntax

[bartveneman]

Summary

Added test coverage for parsing CSS container queries that specify only a container name without conditions, which is valid according to the CSS Containment specification.

Changes

• Added test case for simple container query with a single identifier name (@container sidebar)
• Added test case for container query with hyphenated container name (@container my-layout)
• Both tests verify that the parser correctly identifies the container name as an IDENTIFIER node within the CONTAINER_QUERY node

Details

These tests validate that the parser correctly handles the optional container conditions syntax. According to the CSS spec (referenced in the test comments), container conditions are optional when a container name is specified. The tests ensure that:

1. A container query with just a name is parsed as a CONTAINER_QUERY node
2. The container name is correctly extracted as an IDENTIFIER child node
3. Both simple and hyphenated container names are handled properly

https://claude.ai/code/session_01Ta7yWNuyFFE523YPGg46F7

[codecov-commenter]

Bundle Report

Bundle size has no change ✅

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 95.24%. Comparing base (b5706aa) to head (0c02948).
⚠️ Report is 2 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #204   +/-   ##
=======================================
  Coverage   95.24%   95.24%           
=======================================
  Files          16       16           
  Lines        2881     2881           
  Branches      806      806           
=======================================
  Hits         2744     2744           
  Misses        137      137           

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