chore(build): enable the configuration cache (#38)

* chore(build): enable the configuration cache

Adds org.gradle.configuration-cache and .parallel. The build already ran with
caching and parallel execution but never cached its configuration phase, so
every invocation re-configured from scratch.

Deliberately no org.gradle.isolated-projects. The sweep that prompted this
listed it as the cheap win alongside the configuration cache, but there is a
single :plugin module here — per-project configuration isolation has nothing to
isolate. Enabling it would be noise, so gradle.properties says why. (The
plugin's own output is already isolated-projects-safe for consumers; that was
the earlier BuildService refactor and is a separate concern from this build's
own configuration.)

Verified with ./gradlew build.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* docs(build): correct the configuration-cache lifecycle comment

The configuration cache has been stable since Gradle 8.1, not 9; it is the
.parallel flag that is still incubating in 9.7. Review caught the comment
claiming otherwise. Comment-only change.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 5 <noreply@anthropic.com>

Author: jamesarich

gradle.properties

@@ -1,4 +1,11 @@
 org.gradle.jvmargs=-Xmx2g -Dfile.encoding=UTF-8
 org.gradle.parallel=true
 org.gradle.caching=true
+
+# Configuration cache (stable since Gradle 8.1; .parallel is still incubating in 9.7).
+# No org.gradle.isolated-projects: the build is a
+# single :plugin module, so there is nothing for per-project isolation to separate. (The plugin's
+# own output is already isolated-projects-safe for consumers — see the BuildService refactor.)
+org.gradle.configuration-cache=true
+org.gradle.configuration-cache.parallel=true
 version=0.1.7