Nested container element constraint (`List<List<@NotBlank String>>`) silently generates no adapter

[ah3nan]

A container element constraint inside another container is not supported, and the failure surfaces
late: the processor only warns, no adapter is generated, and validation then throws at runtime.

Reproduction

@Valid
record Direct(List<List<@NotBlank String>> matrix) {}

Validator.instance().validate(new Direct(List.of(List.of("x", ""))));

Compile output

warning: No Constraints Defined
    record Direct(List<List<@NotBlank String>> matrix) {}

No DirectValidationAdapter is generated.

Runtime

java.lang.IllegalArgumentException: No ValidationAdapter for class nest.Nest2$Direct
    at io.avaje.validation.core.CoreAdapterBuilder.buildForType(CoreAdapterBuilder.java:83)
    at io.avaje.validation.core.CoreAdapterBuilder.build(CoreAdapterBuilder.java:60)
    at io.avaje.validation.core.DValidator.adapter(DValidator.java:151)

Expected

Either support the nested container element constraint, or fail the build with an error (not a
warning) so the missing adapter cannot reach production.

Comparison

• Hibernate Validator 9.1.2 validates List<List<@NotBlank String>> and reports
  grid[0].<list element>[1].<list element>.
• avaje List<@NotBlank String> works (element violations reported, albeit with the malformed path
  of Issue 3), and List<@Valid Inner> works and reports items[0].name.