Fix skill origin metadata and macOS source-importer portability

Point SKILL.md origin-repository/origin-path at the renamed
diagrams-drawio repository and workspace path.

openConfined() and the directory walker addressed opened files through
/proc/self/fd, which only exists on Linux, so every file/directory source
import failed on macOS (2 of 150 tests). Keep the procfs path where it is
available and fall back to realpath() plus a dev/inode identity check
against the open handle elsewhere.

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

SKILL.md

@@ -6,8 +6,8 @@ metadata:
   author: workspace-swiss-knife
   version: "2.0"
   spec: agentskills.io/specification
-  origin-repository: git@github.ibm.com:CTOTools-skills-code-agent/drawio-main.git
-  origin-path: $HOME/projects-ibm/cognitive-architect/workspace-skills-code-agent/drawio-main
+  origin-repository: git@github.ibm.com:CTOTools-skills-code-agent/diagrams-drawio.git
+  origin-path: $HOME/projects-skills-code-agent/ws-skills-code-agent/diagrams-drawio
   repository: https://gitea.lego-cloud.eu/home-v1-skills-code-agent/diagrams-drawio
 compatibility: Designed for Cline, Claude Code, GitHub Copilot, OpenAI Codex, and other compatible agent environments
 ---

scripts/src/services/source-importers/index.ts

@@ -1,5 +1,5 @@
 import { constants } from "node:fs";
-import { open, readdir, realpath } from "node:fs/promises";
+import { open, readdir, realpath, stat } from "node:fs/promises";
 import type { FileHandle } from "node:fs/promises";
 import { isAbsolute, relative, resolve } from "node:path";
 
@@ -643,7 +643,7 @@ async function openConfined(candidate: string, root: string): Promise<{ handle:
     throw error;
   }
   try {
-    const canonical = await realpath(`/proc/self/fd/${handle.fd}`);
+    const canonical = await canonicalPathOfOpenHandle(handle, candidate);
     if (!isConfined(root, canonical)) throw new Error("Opened source escapes outside declared root");
     return { handle, canonical };
   } catch (error) {
@@ -652,6 +652,35 @@ async function openConfined(candidate: string, root: string): Promise<{ handle:
   }
 }
 
+let procFdAvailable: boolean | undefined;
+
+/** Path to address an open directory by: its `/proc/self/fd/N` entry on Linux, else its verified canonical path. */
+async function descriptorPath(handle: FileHandle, canonical: string): Promise<string> {
+  if (procFdAvailable === undefined) {
+    try { await realpath(`/proc/self/fd/${handle.fd}`); procFdAvailable = true; } catch { procFdAvailable = false; }
+  }
+  return procFdAvailable ? `/proc/self/fd/${handle.fd}` : canonical;
+}
+
+/**
+ * Resolve the canonical path of an already-opened file. On Linux `/proc/self/fd/N` answers for the
+ * exact descriptor; on macOS/BSD (no procfs) fall back to resolving the candidate path and proving it
+ * names the same inode as the open handle, so a swap between open() and realpath() is still rejected.
+ */
+async function canonicalPathOfOpenHandle(handle: FileHandle, candidate: string): Promise<string> {
+  try {
+    return await realpath(`/proc/self/fd/${handle.fd}`);
+  } catch (error) {
+    if ((error as NodeJS.ErrnoException).code !== "ENOENT") throw error;
+  }
+  const canonical = await realpath(candidate);
+  const [opened, resolved] = await Promise.all([handle.stat(), stat(canonical)]);
+  if (opened.dev !== resolved.dev || opened.ino !== resolved.ino) {
+    throw new Error("Opened source does not match its canonical path");
+  }
+  return canonical;
+}
+
 async function readBounded(handle: FileHandle, limit: number, directory: boolean): Promise<Buffer> {
   const initial = await handle.stat();
   if (!initial.isFile()) throw new Error("Source entry must be a regular file");
@@ -711,12 +740,13 @@ export async function importSource(request: SourceImportRequest): Promise<Source
 
   const results: SourceImportResult[] = [];
   let consumed = 0;
-  const walk = async (directory: FileHandle): Promise<void> => {
-    for (const name of (await readdir(`/proc/self/fd/${directory.fd}`)).sort(codePointCompare)) {
-      const opened = await openConfined(resolve(`/proc/self/fd/${directory.fd}`, name), rootPath);
+  const walk = async (directory: { handle: FileHandle; canonical: string }): Promise<void> => {
+    const base = await descriptorPath(directory.handle, directory.canonical);
+    for (const name of (await readdir(base)).sort(codePointCompare)) {
+      const opened = await openConfined(resolve(base, name), rootPath);
       try {
         const entryInfo = await opened.handle.stat();
-        if (entryInfo.isDirectory()) await walk(opened.handle);
+        if (entryInfo.isDirectory()) await walk(opened);
         else if (entryInfo.isFile()) {
           const dot = name.lastIndexOf("."); const extension = dot >= 0 ? name.slice(dot).toLowerCase() : "";
           if (extensions[request.sourceKind].has(extension)) {
@@ -729,7 +759,7 @@ export async function importSource(request: SourceImportRequest): Promise<Source
       } finally { await opened.handle.close(); }
     }
   };
-  try { await walk(source.handle); }
+  try { await walk(source); }
   finally { await source.handle.close(); }
   if (results.length === 0) throw new Error(`No supported ${request.sourceKind} source files found`);
   const nodeById = new Map<string, DiagramNode>(); const edgeById = new Map<string, DiagramEdge>(); const diagnostics: ImportDiagnostic[] = [];