fix(jsx): honor defaultValue/defaultChecked on input and textarea [#2820]

[viniciusdacal]

Summary

Closes #2820.

<textarea defaultValue="..."> and <input defaultValue="..."> were silently dropped — the React-style uncontrolled-initial-value props have no HTML content attribute, so the compiler's fallback to setAttribute("defaultValue", ...) was a no-op in the browser, and the SSR DOM shim never serialized the assigned IDL property.

Routes them through the existing IDL-property path the framework already uses for value / checked:

• @vertz/native-compiler: is_idl_property now recognizes defaultValue (input, textarea) and defaultChecked (input). Boolean shorthand (<input defaultChecked />) emits __el0.defaultChecked = true. IDL emission stays deferred until after __exitChildren().
• @vertz/ui JSX runtime: IDL_PROPS includes the new keys so the test-time runtime defers them after children too.
• vtz SSR DOM shim: defaultValue setter writes the value attribute on <input> and replaces text content on <textarea>; defaultChecked toggles the checked attribute on <input>. No-op on other elements to preserve plain JS-property semantics.

Public API Changes

• Additions: defaultValue on <input> / <textarea> and defaultChecked on <input> now behave like the React/HTML standard. No type changes — they were already accepted via the catch-all on HTMLAttributes.
• Breaking: none.

Test plan

• cargo test --all (1135 + 3469 + others all green; only the previously-ignored inspector_brk test stays ignored)
• cargo clippy --all-targets -- -D warnings clean
• cargo fmt --all -- --check clean
• vtz test on packages/ui/src/jsx-runtime and packages/ui/src/dom (415 / 415 pass)
• New unit tests added:
  • is_idl_property_default_value (compiler-core)
  • textarea_default_value_static_emits_idl_assignment, input_default_value_static_emits_idl_assignment, input_default_checked_boolean_shorthand_emits_idl_assignment (compiler-core)
  • test_textarea_default_value_serializes, test_input_default_value_serializes, test_input_default_checked_serializes, test_default_value_no_op_on_div (vtz dom_shim)
  • defaultValue / defaultChecked cases in jsx-idl-props.test.ts (@vertz/ui)

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