Memoizer reuses readers initialized with different DynamicMetadataOptions

[Darlokt]

As a continuation of #4464, FormatTools.equalReaders currently compares only the metadata level.
It does not compare validation or reader-specific DynamicMetadataOptions.
Memoizer can therefore deserialize reader state initialized with options that differ from the current request. A current .bfoptions sidecar is also not loaded into the fresh reader before the compatibility check.

This can affect pixel decoding, metadata parsing, and other reader-specific initialization behavior.

Minimal reproduction

String id = "/tmp/options.fake";

FakeReader firstReader = new FakeReader();
DynamicMetadataOptions firstOptions = new DynamicMetadataOptions();
firstOptions.set("reader.option", "first");
firstReader.setMetadataOptions(firstOptions);
try (Memoizer first = new Memoizer(firstReader, 0)) {
  first.setId(id); // saves memo initialized with "first"
}

FakeReader secondReader = new FakeReader();
DynamicMetadataOptions secondOptions = new DynamicMetadataOptions();
secondOptions.set("reader.option", "second");
secondReader.setMetadataOptions(secondOptions);
try (Memoizer second = new Memoizer(secondReader, 0)) {
  second.setId(id);
  assert !second.isLoadedFromMemo(); // fails on the base branch
}

The same stale hit can be reproduced by changing <id>.bfoptions while preserving the primary file.

Expected behavior

Memoizer accepts a cached reader only when all effective metadata options match the current reader.
Built-in options should use value equality.
A custom MetadataOptions implementation that retains identity equality should safely miss the cache.