Replace pcgen.base.logging SPI with java.lang.System.Logger

[Vest]

Context

PCGen-base shipped a tiny custom logging SPI (pcgen.base.logging.Logging + Severity enum) whose explicit purpose, per its Javadoc, was to keep the base library free of external dependencies while letting host applications plug a real backend in via setProcessor(...). The JDK has shipped exactly this SPI since Java 9 as java.lang.System.Logger + System.LoggerFinder, and PCGen's toolchain is now Java 25 (PCGen-base/build.gradle, PCGen-Formula/build.gradle).

So the custom abstraction is pure tax: a maintenance liability that duplicates a JDK-standard SPI which contributors already recognise on sight.

What this change does

• Deletes PCGen-base/code/src/java/pcgen/base/logging/Logging.java and Severity.java.
• Removes exports pcgen.base.logging; from PCGen-base/code/src/java/module-info.java.
• Migrates the only two callers (both in PCGen-Formula) to System.Logger:
  • pcgen.base.formula.function.GetOptionalFunction
  • pcgen.base.formula.visitor.EvaluateVisitor

The migration pattern is one-for-one:

-import pcgen.base.logging.Logging;
-import pcgen.base.logging.Severity;
+import java.lang.System.Logger;
+import java.lang.System.Logger.Level;
 …
+private static final Logger LOG = System.getLogger(MyClass.class.getName());
 …
-Logging.log(Severity.WARNING, () -> "msg");
+LOG.log(Level.WARNING, () -> "msg");

System.Logger provides the Supplier<String> overload, so the existing lazy-evaluation pattern carries over unchanged.

Runtime behaviour

Unchanged. The JDK's default LoggerFinder routes System.Logger to java.util.logging, which is exactly the pipeline root code/'s pcgen.util.Logging (and its static {} bootstrap of logging.properties, SourceLogFormatter, LoggingRecorder, …) already configures. The new logger names (pcgen.base.formula.function.GetOptionalFunction, pcgen.base.formula.visitor.EvaluateVisitor) sit under the existing pcgen.* JUL parent, so they pick up current config with no logging.properties edits.

PCGen-base does not need requires java.logging; because System.Logger / System.LoggerFinder / System.getLogger all live in java.base. The base module is still dependency-free; if a host ever wants to plug in SLF4J / Log4j2 instead of JUL, it does so via the JDK-standard LoggerFinder SPI rather than a custom setProcessor call.

Scope, intentional non-scope

In scope:

• PCGen-base SPI deletion + module-info edit
• Two PCGen-Formula call-site migrations

Out of scope (deliberately — separate, independent follow-ups):

• Root code/'s pcgen.util.Logging is untouched. It continues to own JUL bootstrap, PCGenLogLevel.LST_* levels, isDebugMode toggle, localization, error-count helpers, and LoggingRecorder wiring. None of that disappears by switching the base SPI.
• No backend swap (JUL → Log4j2 / Logback / SLF4J).

Verification

• grep -rn "pcgen\.base\.logging" PCGen-base PCGen-Formula code → no matches.
• ./gradlew :PCGen-base:compileJava :PCGen-Formula:compileJava → BUILD SUCCESSFUL.
• ./gradlew :PCGen-base:test :PCGen-Formula:test → BUILD SUCCESSFUL.

Diff: 5 files changed, +14 / −126.

[Vest]

I'd like to have a single logging system for the entire project. Until now, we have 3.