fix(extractor): implement two-pass OCI extraction and fix path normalization

This commit resolves a long-standing issue where OCI archives (and the "hybrid" format produced by Docker Desktop's containerd store) would fail to scan
silently.

Root Cause:
The previous implementation attempted to pipe a single blob stream to both a
JSON parser and a tar extractor simultaneously. This resulted in stream
corruption, causing both parsers to fail and the plugin to swallow errors,
ultimately returning zero results to the CLI.

Changes:
- Implemented a two-pass extraction strategy:
  1. Pass 1: Scans the archive to extract only JSON metadata (manifests, configs).
  2. Pass 2: Re-opens the archive to extract only the layers needed for the 
     target platform.
- Robust Path Parsing: Added .filter(Boolean) to path splitting logic to 
  gracefully handle archives using absolute paths (starting with /).
- Code Cleanup: Removed the unused platformInfo return variable as identified
  during review.

Impact:
- Successfully restores scanning functionality for images like ubuntu:latest and 
  mongo:8.0.17 on systems using the containerd image store.
- Improves error visibility by removing blanket catch-alls that hid failures.

Tickets: CN-731, CN-659, CN-657, CN-169, CN-554

Author: bgardiner

lib/extractor/index.ts

@@ -1,3 +1,4 @@
+import * as Debug from "debug";
 import path = require("path");
 import {
   getLayersFromPackages,
@@ -20,6 +21,8 @@ import {
   OciArchiveManifest,
 } from "./types";
 
+const debug = Debug("snyk");
+
 export class InvalidArchiveError extends Error {
   constructor(message) {
     super();
@@ -157,10 +160,14 @@ export async function extractImageContent(
 async function extractArchiveContentFallback(
   extractors: Map<ImageType, ArchiveExtractor>,
 ): Promise<[ExtractedLayersAndManifest, ArchiveExtractor]> {
-  for (const extractor of extractors.values()) {
+  for (const [imageType, extractor] of extractors.entries()) {
     try {
       return [await extractor.getLayersAndManifest(), extractor];
     } catch (error) {
+      // imageType is a string enum value like "docker-archive", "oci-archive"
+      debug(
+        `Error getting layers and manifest content from ${imageType} archive: ${error.message}`,
+      );
       continue;
     }
   }