Vue 3.4: faster compiles and a more mature reactivity core

Vue 3.4 is a strong minor because it improves the everyday development loop while also tightening some long-running implementation details.

The headline items are a rewritten template parser that is roughly twice as fast, better SFC build performance, a more efficient reactivity system, stable `defineModel`, `v-bind` same-name shorthand, and clearer hydration mismatch diagnostics.

For teams already committed to Vue, 3.4 is less about shiny new APIs and more about a framework that feels faster, more accurate, and more predictable in daily use.