Pin deterministic completion merge (#176)

Author: chubes4

.github/workflows/maintain-docs.yml

@@ -4,7 +4,7 @@ env:
   # Advance this revision and all package digests together when package bytes change.
   DOCS_AGENT_PACKAGE_REVISION: a39d9db230eb9e0b72ed84465f4d61bd8dda1bab
   # Advance independently when the post-command completion validator changes.
-  DOCS_AGENT_COMPLETION_CONTRACT_REVISION: 44f1e60e9278dd351fafea53434999de4782514b
+  DOCS_AGENT_COMPLETION_CONTRACT_REVISION: b136f9bc84e6f0ad9d5d0d5cdbb3df9c62e382e2
 
 'on':
   workflow_call:

tests/validate-docs-agent-packages.php

@@ -85,7 +85,7 @@
 $assert( str_contains( $maintain_docs_workflow, 'sourceDelta:$sourceDelta' ), 'maintain-docs.yml must retain caller-known bounded source deltas in the portable recipe.' );
 $assert( str_contains( $maintain_docs_workflow, 'source_delta must contain at least one caller-bounded item for maintenance.' ), 'maintain-docs.yml must reject empty maintenance source deltas before execution.' );
 $assert( str_contains( $maintain_docs_workflow, 'validate-docs-agent-completion.php' ), 'maintain-docs.yml must execute the Docs Agent-owned completion validator.' );
-$completion_contract_revision = '44f1e60e9278dd351fafea53434999de4782514b';
+$completion_contract_revision = 'b136f9bc84e6f0ad9d5d0d5cdbb3df9c62e382e2';
 $assert( str_contains( $maintain_docs_workflow, 'DOCS_AGENT_COMPLETION_CONTRACT_REVISION: ' . $completion_contract_revision ), 'maintain-docs.yml must pin the completion validator to its immutable implementation commit.' );
 $assert( str_contains( $maintain_docs_workflow, 'Automattic/docs-agent/$DOCS_AGENT_COMPLETION_CONTRACT_REVISION/scripts/validate-docs-agent-completion.php' ), 'maintain-docs.yml must fetch the validator independently of native package provenance.' );
 $historical_validator = shell_exec( 'git -C ' . escapeshellarg( $root ) . ' show ' . escapeshellarg( $completion_contract_revision . ':scripts/validate-docs-agent-completion.php' ) );