BUILD PR: add simple script to run shared extraction guard.

Author: DavidQ

docs/dev/CODEX_COMMANDS.md

@@ -1,7 +1,8 @@
 MODEL: GPT-5.3-codex
 REASONING: high
 COMMAND:
-Execute docs/pr/BUILD_PR_SHARED_EXTRACTION_21_OPTIONAL_NPM_PREHOOK_GUARD.md exactly.
-Edit only package.json under defined rules.
-Fail fast if conditions not met.
-Package delta to <project folder>/tmp/BUILD_PR_SHARED_EXTRACTION_21_OPTIONAL_NPM_PREHOOK_GUARD_delta.zip
+Execute docs/pr/BUILD_PR_SHARED_EXTRACTION_22_ADD_GUARD_RUN_SCRIPT.md exactly.
+Create only:
+- tools/dev/runSharedExtractionGuard.sh
+Do not expand scope.
+Package delta to <project folder>/tmp/BUILD_PR_SHARED_EXTRACTION_22_ADD_GUARD_RUN_SCRIPT_delta.zip

docs/dev/COMMIT_COMMENT.txt

@@ -1 +1 @@
-BUILD PR: optional npm prehook for shared extraction guard.
+BUILD PR: add simple script to run shared extraction guard.

docs/dev/reports/change_summary.txt

@@ -1 +1 @@
-Optional guard auto-run via npm prehooks.
+Adds simple guard runner script.

docs/dev/reports/validation_checklist.txt

@@ -1 +1 @@
-prehook added correctly
+script added correctly

docs/pr/BUILD_PR_SHARED_EXTRACTION_22_ADD_GUARD_RUN_SCRIPT.md

@@ -0,0 +1,30 @@
+# BUILD_PR_SHARED_EXTRACTION_22_ADD_GUARD_RUN_SCRIPT
+
+## Purpose
+Provide a simple cross-platform way to execute the shared-extraction guard without relying on npm scripts.
+
+## Single PR Purpose
+Create a single script:
+
+tools/dev/runSharedExtractionGuard.sh
+
+## Exact Files Allowed
+1. tools/dev/runSharedExtractionGuard.sh (new file)
+
+## Exact File Content
+
+```bash
+#!/usr/bin/env bash
+node tools/dev/checkSharedExtractionGuard.mjs
+```
+
+## Rules
+- no other files
+- no logic changes
+- no npm dependency
+- no config changes
+
+## Validation
+1. file exists
+2. script runs guard
+3. no other files changed

tools/dev/runSharedExtractionGuard.sh

@@ -0,0 +1,2 @@
+#!/usr/bin/env bash
+node tools/dev/checkSharedExtractionGuard.mjs