Properties with @api (or in @api classes) should be treated as both
read and written by external code. Without this, @api properties were
falsely reported as "never written".

Demonstrates the shipmonk.deadProperty.neverWritten identifier
alongside the existing neverRead, deadConstant, deadMethod and
deadEnumCase identifiers.

Adds a PropertyWrites test class and corresponding
shouldMarkPropertyAsWritten override in the custom provider,
verifying the extension point suppresses neverWritten errors
independently of other member types.

PropertyAccessCollector only tracked promoted property writes for
`new` expressions. This adds tracking for static calls to __construct
(e.g. parent::__construct()), so promoted properties in parent classes
are correctly marked as written.

Instead of detecting promoted property writes at each call site (new,
parent::__construct, etc.), emit them once inside the constructor
definition via InClassMethodNode. Transitivity handles propagation
from any caller automatically.

This also removes getDerivedUsages from ProvidedUsagesCollector, as
it is no longer needed — provider-marked constructor usages propagate
to promoted property writes through the same transitivity mechanism.

Extract buildTransitiveErrorMessages to produce property-aware
messages ("transitively never read/written") instead of always
saying "transitively also unused".

…e properties

Virtual properties (hooks that don't reference the backing value) without
a set hook cannot be written to, so they should not be tracked for
neverWritten detection. This replaces the previous interface-only check
with proper virtual property detection that also handles closures, arrow
functions, and anonymous classes inside hook bodies correctly.