fix(SEC-REVIEW-4-7): Address remaining MEDIUM security review findings

- Graceful container shutdown: detect "not running" containers and skip
  force-remove escalation, only SIGKILL for genuine stop failures
- data: URI stripping: add security audit logging via NestJS Logger
  when data: URIs are blocked in markdown links and images
- Orchestrator bootstrap: replace void bootstrap() with .catch() handler
  for clear startup failure logging and clean process.exit(1)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

apps/api/src/knowledge/utils/markdown.ts

@@ -124,6 +124,7 @@ const SANITIZE_OPTIONS: sanitizeHtml.IOptions = {
       const href = attribs.href;
       // Strip data: URI scheme from links
       if (href?.trim().toLowerCase().startsWith("data:")) {
+        logger.warn(`Blocked data: URI in link href`);
         const { href: _removed, ...safeAttribs } = attribs;
         return {
           tagName,
@@ -149,6 +150,7 @@ const SANITIZE_OPTIONS: sanitizeHtml.IOptions = {
     img: (tagName: string, attribs: sanitizeHtml.Attributes) => {
       const src = attribs.src;
       if (src?.trim().toLowerCase().startsWith("data:")) {
+        logger.warn(`Blocked data: URI in image src`);
         const { src: _removed, ...safeAttribs } = attribs;
         return {
           tagName,

apps/orchestrator/src/main.ts

@@ -17,4 +17,7 @@ async function bootstrap() {
   logger.log(`🚀 Orchestrator running on http://${host}:${String(port)}`);
 }
 
-void bootstrap();
+bootstrap().catch((err: unknown) => {
+  logger.error("Failed to start orchestrator", err instanceof Error ? err.stack : String(err));
+  process.exit(1);
+});

apps/orchestrator/src/spawner/docker-sandbox.service.spec.ts

@@ -243,11 +243,25 @@ describe("DockerSandboxService", () => {
       expect(mockContainer.remove).toHaveBeenCalledWith({ force: false });
     });
 
-    it("should fall back to force remove when graceful stop fails", async () => {
+    it("should remove without force when container is not running", async () => {
       const containerId = "container-123";
 
       (mockContainer.stop as ReturnType<typeof vi.fn>).mockRejectedValueOnce(
-        new Error("Container already stopped")
+        new Error("container is not running")
+      );
+
+      await service.removeContainer(containerId);
+
+      expect(mockContainer.stop).toHaveBeenCalledWith({ t: 10 });
+      // Not-running containers are removed without force, no escalation needed
+      expect(mockContainer.remove).toHaveBeenCalledWith({ force: false });
+    });
+
+    it("should fall back to force remove when graceful stop fails with unknown error", async () => {
+      const containerId = "container-123";
+
+      (mockContainer.stop as ReturnType<typeof vi.fn>).mockRejectedValueOnce(
+        new Error("Connection timeout")
       );
 
       await service.removeContainer(containerId);

apps/orchestrator/src/spawner/docker-sandbox.service.ts

@@ -361,8 +361,17 @@ export class DockerSandboxService {
       this.logger.log(`Container gracefully stopped and removed: ${containerId}`);
       return;
     } catch (gracefulError) {
+      const errMsg = gracefulError instanceof Error ? gracefulError.message : String(gracefulError);
+
+      // If container is already stopped, just remove without force
+      if (errMsg.includes("is not running") || errMsg.includes("304")) {
+        this.logger.log(`Container ${containerId} already stopped, removing without force`);
+        await container.remove({ force: false });
+        return;
+      }
+
       this.logger.warn(
-        `Graceful stop failed for container ${containerId}, falling back to force remove: ${gracefulError instanceof Error ? gracefulError.message : String(gracefulError)}`
+        `Graceful stop failed for container ${containerId}, falling back to force remove: ${errMsg}`
       );
     }