[wieslawsoltes]

Summary

• expose a pointer-driven pressed target to selector matching and implement inclusive-ancestor :active semantics
• index :active dependencies separately from :hover, including subject, descendant, sibling, functional-pseudo, pseudo-element, and custom-property invalidation scopes
• enter active state before down-event dispatch and clear it before up-event dispatch while retaining independent click-target tracking
• carry the active dependency index through document cascade switching, low-memory compaction, navigation, teardown, and memory accounting

Validation debt

Per the current implementation-throughput directive, build, native/browser/WPT, performance, memory, lifecycle, package, and CI validation were not run. These remain explicit debt under #478 and the parent epics before release promotion.

Closes #478