Make named colors and explicit fills replace each other in the text
notation. Raw nil, empty or nonstandard fills previously masked a new
named color, making generated source color edits no-ops (F225).
The notation regressions fail seven of eight assertions before the fix.
Validation: notation/text suites, transitive source and frontend controls,
full common JVM/JS, frontend and consumers, plus lint and formatting.
Golden data and production behavior are unchanged.
AI-assisted-by: GPT-6
e4239e02b7