docs: unify PIT — trim generic invocation mechanics to the policy

Slim the CLAUDE.md PIT pointer to the uniform cross-repo form and trim the
'Run mutation tests' block (CLAUDE.md + README) to the command plus a short note;
the @{argLine}/jacoco rationale now lives only in the workspace PIT policy.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_017i6A5bMhgCSbiKibQhxwuz

Author: claude

CLAUDE.md

@@ -16,14 +16,11 @@ mvn install -Dgpg.skip=true  # Install to local repo without GPG signing
 mvn test -Dtest=StreamBufferTest#testSimpleRoundTrip
 ```
 
-**Run mutation tests:**
+**Run mutation tests** (the `test-compile` prefix is required — see the
+[PIT policy](../workspace/policies/pit-mutation-testing.md)):
 ```bash
 mvn test-compile org.pitest:pitest-maven:mutationCoverage
 ```
-The `test-compile` prefix is required: it triggers JaCoCo's `prepare-agent` so the
-surefire `@{argLine}` resolves. The bare `mvn org.pitest:pitest-maven:mutationCoverage`
-fails with `NoSuchFileException: {argLine}`. See
-[`../workspace/policies/pit-mutation-testing.md`](../workspace/policies/pit-mutation-testing.md).
 
 **Run JMH benchmarks:**
 
@@ -116,9 +113,7 @@ See [`../workspace/policies/ci-test-diagnostics.md`](../workspace/policies/ci-te
 ## PIT Mutation Testing
 
 See [`../workspace/policies/pit-mutation-testing.md`](../workspace/policies/pit-mutation-testing.md).
-Run PIT with the lifecycle prefix — `mvn test-compile org.pitest:pitest-maven:mutationCoverage`
-(the bare goal fails with `NoSuchFileException: {argLine}`). The gate covers the whole
-`net.ladenthin.streambuffer` package at a 100% threshold.
+Run PIT with the lifecycle prefix — `mvn test-compile org.pitest:pitest-maven:mutationCoverage`.
 
 ## JPMS Module Descriptor
 

README.md

@@ -381,8 +381,7 @@ Run a single test:
 mvn test -Dtest=StreamBufferTest#testSimpleRoundTrip
 ```
 
-Run mutation tests (the `test-compile` prefix is required so JaCoCo's `prepare-agent`
-resolves the surefire `@{argLine}`; the bare goal fails with `NoSuchFileException: {argLine}`):
+Run mutation tests (the `test-compile` prefix is required so PIT inherits JaCoCo's agent):
 
 ```bash
 mvn test-compile org.pitest:pitest-maven:mutationCoverage