Preserve inline textual CSS properties through recascade #848

Problem

The exact Linux full-V8 runtime package gate exposed two problems in webscene_css_effect_values_tests:

1. several ID selectors in the fixture had lower specificity than the existing #effects > span rule, so the original compound-filter failure was a stale test expectation;
2. a real cascade defect remained: CSSOM writes for textual properties whose native property mask is zero (including filter, clip-path, masks, and related retained effects) were stored in CSSStyleDeclaration, but a later recascade cleared their computed textual values and did not replay the inline declaration.

This made element.style.filter = 'blur(4px)' report authored state while the retained scene continued to use the stylesheet brightness(0.5). It also required correct author !important precedence over normal inline declarations.

Fix scope

• replay cold inline declarations after stylesheet declarations during a one-node recascade;
• preserve author !important precedence and restore the inline value when the important stylesheet is removed;
• route both generic and named CSSOM setters for cold properties through the normal one-node cascade;
• return the final cascaded retained-effect value from computed style;
• correct fixture specificity and current mask metadata expectations;
• retain the 4,096-node/100-cycle performance, scene-order, localized-damage, and memory gates.

Acceptance

• inline filter updates computed style and retained blur damage immediately;
• author !important overrides normal inline filter, and removing the rule restores the inline value;
• compound effect values retain authored function order;
• the focused full-V8 executable passes with 4,096 nodes, 100 selector cycles, localized 22x16 blur damage, and zero retained heap growth;
• no subtree recascade or mutation-lived winner cache is introduced.

Implementation

Implemented on fix/css-compound-filter-id-848 in commit 9ebf6dbc.