fix(codex): keep commented TOML fields, follow symlinked config surfaces

readTomlMeta was dropping any field with a trailing `# comment` (common in
real agents/*.toml). readSkills/readAgents/readRules used bare
isDirectory()/isFile(), which miss symlinked entries per cc-discovery.js's
own documented Dirent quirk — reused its isDirLike/isFileLike instead
(exporting isDirLike from cc-discovery.js, which wasn't previously public).
Also swapped the "never walks outside" test for one that actually exercises
a symlink escape, and dropped the unnecessary isUnder re-export.

server/__tests__/codex-discovery.test.js

@@ -85,6 +85,14 @@ describe("codex-discovery", () => {
     assert.equal(meta.model, "gpt-5.3-codex-spark");
   });
 
+  it("keeps a field with a trailing inline comment, and keeps a '#' that is inside the string", () => {
+    const meta = cx.readTomlMeta(
+      'model = "gpt-5.4"  # default\n' + 'description = "uses # for headings"\n'
+    );
+    assert.equal(meta.model, "gpt-5.4");
+    assert.equal(meta.description, "uses # for headings");
+  });
+
   it("reads a rule file's preview", () => {
     write(
       path.join(TMP, "rules", "no-force-push.rules"),
@@ -119,11 +127,20 @@ describe("codex-discovery", () => {
     assert.equal(project.exists, false);
   });
 
-  it("never walks outside the codex roots", () => {
-    write(path.join(TMP, "skills", "esc", "SKILL.md"), "x");
-    for (const row of cx.readSkills({ cwd: REPO })) {
+  it("follows a symlinked skill dir (a supported install pattern) without ever reporting a path outside the codex roots", () => {
+    const outside = fs.mkdtempSync(path.join(os.tmpdir(), "codex-disc-outside-"));
+    write(path.join(outside, "SKILL.md"), "---\nname: linked\n---\nbody");
+    fs.symlinkSync(outside, path.join(TMP, "skills", "linked"), "dir");
+
+    const rows = cx.readSkills({ cwd: REPO });
+    const linked = rows.find((r) => r.name === "linked");
+    assert.ok(linked, "a symlinked skill directory must still be discovered");
+    assert.equal(linked.frontmatter.name, "linked");
+    for (const row of rows) {
       assert.ok(row.file.startsWith(TMP) || row.file.startsWith(REPO));
+      assert.ok(!row.file.startsWith(outside));
     }
+    fs.rmSync(outside, { recursive: true, force: true });
   });
 
   it("summarizes counts and roots in the overview", () => {