Migrate from vue/compiler-dom to parse5

Editor assessment

`refactor: migrate from vue/compiler-dom to parse5` records the technology swap but not the reason — unvendoring, correctness, size — which is the interesting half of a dependency migration. Refactor is defensible for an internal replacement, and the subject is legible alone. No body supplies the motivation or any behavioral notes, so the message is a bare mechanical fact. Style is clean: imperative, period-free, no junk. Understandable and correct but uninstructive — the acceptable tier for competent-but-thin communication.