feat: add prompt injection check workflow for content security (#324)

New bundled workflow `prompt-injection-check` scans scraped content for
prompt injection patterns (role assumption, instruction overrides,
delimiter injection, hidden instructions, encoded payloads) using AI.

Flags suspicious content without removing it — preserves documentation
accuracy while warning about adversarial content. Added as first stage
in both `default` and `security-focus` workflows so it runs automatically
with --enhance-level >= 1.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

tests/test_workflow_prompt_injection.py

@@ -0,0 +1,94 @@
+"""Tests for prompt injection check workflow (#324).
+
+Validates that:
+- prompt-injection-check.yaml is a valid bundled workflow
+- default.yaml includes injection_scan as its first stage
+- security-focus.yaml includes injection_scan as its first stage
+- The workflow YAML is structurally correct
+"""
+
+from __future__ import annotations
+
+import yaml
+
+
+def _load_bundled_yaml(name: str) -> dict:
+    """Load a bundled workflow YAML by name."""
+    from importlib.resources import files as importlib_files
+
+    for suffix in (".yaml", ".yml"):
+        try:
+            ref = importlib_files("skill_seekers.workflows").joinpath(name + suffix)
+            return yaml.safe_load(ref.read_text(encoding="utf-8"))
+        except (FileNotFoundError, TypeError, ModuleNotFoundError):
+            continue
+    raise FileNotFoundError(f"Bundled workflow '{name}' not found")
+
+
+class TestPromptInjectionCheckWorkflow:
+    """Validate the standalone prompt-injection-check workflow."""
+
+    def test_workflow_loads(self):
+        data = _load_bundled_yaml("prompt-injection-check")
+        assert data["name"] == "prompt-injection-check"
+
+    def test_has_stages(self):
+        data = _load_bundled_yaml("prompt-injection-check")
+        assert "stages" in data
+        assert len(data["stages"]) >= 1
+
+    def test_injection_scan_stage_present(self):
+        data = _load_bundled_yaml("prompt-injection-check")
+        stage_names = [s["name"] for s in data["stages"]]
+        assert "injection_scan" in stage_names
+
+    def test_injection_scan_has_prompt(self):
+        data = _load_bundled_yaml("prompt-injection-check")
+        scan_stage = next(s for s in data["stages"] if s["name"] == "injection_scan")
+        assert scan_stage.get("prompt")
+        assert "prompt injection" in scan_stage["prompt"].lower()
+
+    def test_injection_scan_targets_all(self):
+        data = _load_bundled_yaml("prompt-injection-check")
+        scan_stage = next(s for s in data["stages"] if s["name"] == "injection_scan")
+        assert scan_stage["target"] == "all"
+
+    def test_applies_to_all_source_types(self):
+        data = _load_bundled_yaml("prompt-injection-check")
+        applies = data.get("applies_to", [])
+        assert "doc_scraping" in applies
+        assert "github_analysis" in applies
+        assert "codebase_analysis" in applies
+
+    def test_post_process_metadata(self):
+        data = _load_bundled_yaml("prompt-injection-check")
+        meta = data.get("post_process", {}).get("add_metadata", {})
+        assert meta.get("security_scanned") is True
+
+
+class TestDefaultWorkflowHasInjectionScan:
+    """Validate that default.yaml runs injection_scan first."""
+
+    def test_injection_scan_is_first_stage(self):
+        data = _load_bundled_yaml("default")
+        assert data["stages"][0]["name"] == "injection_scan"
+
+    def test_injection_scan_has_prompt(self):
+        data = _load_bundled_yaml("default")
+        scan_stage = data["stages"][0]
+        assert scan_stage.get("prompt")
+        assert "injection" in scan_stage["prompt"].lower()
+
+
+class TestSecurityFocusHasInjectionScan:
+    """Validate that security-focus.yaml runs injection_scan first."""
+
+    def test_injection_scan_is_first_stage(self):
+        data = _load_bundled_yaml("security-focus")
+        assert data["stages"][0]["name"] == "injection_scan"
+
+    def test_injection_scan_has_prompt(self):
+        data = _load_bundled_yaml("security-focus")
+        scan_stage = data["stages"][0]
+        assert scan_stage.get("prompt")
+        assert "injection" in scan_stage["prompt"].lower()