fix(javascript): retain partial indexed source map facts

Share section classification across declaration analysis and mapping parsing. Preserve external URLs, malformed section reasons, section paths and safe sibling declarations without fetching nested maps.

Refs #5466. All 50 focused tests passed, including real CLI and stdio MCP regressions; typecheck and lint passed.

src/application/javascript/JavaScriptArtifactGraphStructure.ts

@@ -293,6 +293,33 @@ export const addJavaScriptArtifactFiles = (
         asset: target,
         ...javascriptArtifactAnalysisScopes["source-map"],
         limitation: sourceMap.limitation,
+        ...(sourceMap.external_sections === undefined &&
+        sourceMap.invalid_sections === undefined
+          ? {}
+          : {
+              details: {
+                ...(sourceMap.external_sections === undefined
+                  ? {}
+                  : {
+                      external_sections: sourceMap.external_sections.map(
+                        ({ section_path, url }) => ({
+                          section_path: [...section_path],
+                          url,
+                        }),
+                      ),
+                    }),
+                ...(sourceMap.invalid_sections === undefined
+                  ? {}
+                  : {
+                      invalid_sections: sourceMap.invalid_sections.map(
+                        ({ section_path, reason }) => ({
+                          section_path: [...section_path],
+                          reason,
+                        }),
+                      ),
+                    }),
+              },
+            }),
       });
     const inlineScripts = inlineScriptsByPath.get(file.path);
     if (inlineScripts !== undefined)