breaking: wrap declaration values in a Value node

[bartveneman]

BREAKING CHANGES:

• Declaration.value now returns VALUE node instead of raw string
• Declaration.values property removed
• Declaration.children now returns [VALUE] instead of value tokens
• parse_value() function returns CSSNode instead of CSSNode[]

Add VALUE node type (19) to wrap all declaration value tokens.
Each declaration now has a single VALUE child node that contains
the individual value tokens (IDENTIFIER, DIMENSION, etc.) as its
children.

Implementation changes:

• Add VALUE constant (19) in arena.ts
• Update NODES_PER_KB from 270 to 325 (+20% for VALUE wrappers)
• Modify CSSNode.value getter to return VALUE node for declarations
• Remove CSSNode.values getter (redundant)
• Update ValueParser.parse_value() to return single VALUE node
• Update DeclarationParser to create VALUE node for empty values
• Export VALUE from constants.ts
• Update 1068+ tests to use new API

Migration guide:
OLD: const text = declaration.value // "10px 20px"
OLD: const tokens = declaration.values // [DIMENSION, DIMENSION]
NEW: const valueNode = declaration.value // VALUE node
NEW: const text = valueNode.text // "10px 20px"
NEW: const tokens = valueNode.children // [DIMENSION, DIMENSION]

[codecov-commenter]

Codecov Report

❌ Patch coverage is 87.50000% with 3 lines in your changes missing coverage. Please review.
✅ Project coverage is 95.09%. Comparing base (ab661d7) to head (3c2e180).

Files with missing lines	Patch %	Lines
src/parse-value.ts	78.57%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #97      +/-   ##
==========================================
+ Coverage   95.07%   95.09%   +0.01%     
==========================================
  Files          15       15              
  Lines        2559     2567       +8     
  Branches      662      665       +3     
==========================================
+ Hits         2433     2441       +8     
  Misses        126      126              

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[codecov-commenter]

Bundle Report

Changes will increase total bundle size by 850 bytes (0.62%) ⬆️. This is within the configured threshold ✅

Detailed changes

Bundle name	Size	Change
@projectwallace/css-parser-esm	138.76kB	850 bytes (0.62%) ⬆️

Affected Assets, Files, and Routes:

view changes for bundle: @projectwallace/css-parser-esm

Assets Changed:

Asset Name	Size Change	Total Size	Change (%)
parse-*.js	607 bytes	8.39kB	7.8% ⚠️
parse-*.js	220 bytes	6.93kB	3.28%
css-*.js	-180 bytes	16.55kB	-1.08%
arena.js	173 bytes	10.91kB	1.61%
constants.js	23 bytes	2.03kB	1.14%
index.js	7 bytes	1.8kB	0.39%

Files in parse-*.js:

• ./src/parse-value.ts → Total Size: 7.8kB

Files in parse-*.js:

• ./src/parse-declaration.ts → Total Size: 6.29kB

Files in css-*.js:

• ./src/css-node.ts → Total Size: 15.71kB

Files in arena.js:

• ./src/arena.ts → Total Size: 10.01kB

Files in constants.js:

• ./src/constants.ts → Total Size: 681 bytes