fix: harden CI validators, shell scripts, and expand test suite

- Add try-catch around readFileSync in validate-agents, validate-commands,
  validate-skills to handle TOCTOU races and file read errors
- Add validate-hooks.js and all test suites to package.json test script
  (was only running 4/5 validators and 0/4 test files)
- Fix shell variable injection in observe.sh: use os.environ instead of
  interpolating $timestamp/$OBSERVATIONS_FILE into Python string literals
- Fix $? always being 0 in start-observer.sh: capture exit code before
  conditional since `if !` inverts the status
- Add OLD_VERSION validation in release.sh and use pipe delimiter in sed
  to avoid issues with slash-containing values
- Add jq dependency check in evaluate-session.sh before parsing config
- Sync .cursor/ copies of all modified shell scripts

package.json

@@ -75,7 +75,7 @@
   "scripts": {
     "postinstall": "echo '\\n  ecc-universal installed!\\n  Run: npx ecc-install typescript\\n  Docs: https://github.com/affaan-m/everything-claude-code\\n'",
     "lint": "eslint . && markdownlint '**/*.md' --ignore node_modules",
-    "test": "node scripts/ci/validate-agents.js && node scripts/ci/validate-commands.js && node scripts/ci/validate-rules.js && node scripts/ci/validate-skills.js"
+    "test": "node scripts/ci/validate-agents.js && node scripts/ci/validate-commands.js && node scripts/ci/validate-rules.js && node scripts/ci/validate-skills.js && node scripts/ci/validate-hooks.js && node tests/lib/utils.test.js && node tests/lib/package-manager.test.js && node tests/hooks/hooks.test.js && node tests/integration/hooks.test.js"
   },
   "devDependencies": {
     "@eslint/js": "^9.39.2",