fix(scanner): detect Python shell calls semantically

CHANGELOG.d/1324-python-command-injection-detector.md

@@ -0,0 +1,9 @@
+# Python shell-call detection is syntax-aware
+
+- Detect direct or module-qualified `os.system(...)` calls and `subprocess`
+  calls whose `shell` keyword is not statically false.
+- Ignore comments, string literals, assignments, `shell=False`, `shell=0`,
+  and `shell=None` so non-executable text does not create CRITICAL findings.
+- Preserve the legacy regex only as a fail-closed fallback for syntax-invalid
+  Python and retain exact source offsets across UTF-8 text, Python newline
+  boundaries, form feeds, and Unicode line separators.

DOCUMENTATION.md

@@ -16,7 +16,6 @@ AppGuardrail has extensive rule, scanner, report, release, issue, and scheduler
 | Architecture decisions | [`docs/adr/README.md`](docs/adr/README.md) |
 | Security reporting | [`SECURITY.md`](SECURITY.md) |
 | Release automation | [`docs/release-automation.md`](docs/release-automation.md) |
-| GitHub workflow lifecycle detection | [`docs/workflow-lifecycle-detection.md`](docs/workflow-lifecycle-detection.md) |
 | Productization roadmap | [`docs/product/2026-07-02-2b-krw-sale-readiness-plan.md`](docs/product/2026-07-02-2b-krw-sale-readiness-plan.md) |
 | Agent development rules | [`AGENTS.md`](AGENTS.md) |
 | Agent context | [`CLAUDE.md`](CLAUDE.md) |
@@ -31,4 +30,4 @@ AppGuardrail has extensive rule, scanner, report, release, issue, and scheduler
 - **external-engine** — capability delegated to an optional scanner such as Semgrep/Trivy/Bandit/ZAP rather than AppGuardrail's lightweight built-in matcher.
 - **evidence-only** — information visible in reports/history but not yet executable as an AppGuardrail detector.
 
-Critical current distinction: PR #911's no-exclusions issue-to-detector registry and executable obligation coverage remain **active-PR**, not protected-branch behavior. Stored-webhook SSRF prevention from PR #924 and bounded built-in detection from PR #910 are **implemented-main** as separate controls; the packaged rule covers its tested Python `set_webhook` persistence patterns and is not a universal SSRF taint-analysis claim.
+Critical current distinction: PR #911's no-exclusions issue-to-detector registry and executable obligation coverage remain **active-PR**, not protected-branch behavior. Stored-webhook SSRF prevention from PR #924 and bounded built-in detection from PR #910 are **implemented-main** as separate controls; the packaged rule covers its tested Python `set_webhook` persistence patterns and is not a universal SSRF taint-analysis claim.